List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Abbreviations and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Standards and Organizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Chapter 1—Housing History and Purpose

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

Preurban Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

Ephemeral Dwellings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

Episodic Dwellings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

Periodic Dwellings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

Seasonal Dwellings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

Semipermanent Dwellings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

Permanent Dwellings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

Urbanization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

Trends in Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7

Chapter 2—Basic Principles of Healthy Housing 

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

Fundamental Physiologic Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

Fundamental Psychologic Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3

Protection Against Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3

Protection Against Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

Protection Against Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

Fire Extinguishers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

Protection Against Toxic Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

Chapter 3—Housing Regulations

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

Zoning, Housing Codes, and Building Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2

Zoning and Zoning Ordinances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3

Exceptions to the Zoning Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5

Housing Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6

Building Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13

Healthy Housing Reference Manual 1

Contents
Chapter 4—Disease Vectors and Pests

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1

Disease Vectors and Pests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1

Rodents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1

Cockroaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4

Fleas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-6

Flies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-7

Termites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-8

Fire Ants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-13

Mosquitoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-15

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-17

Chapter 5—Indoor Air Pollutants and Toxic Materials

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1

Indoor Air Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1

Biologic Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1

Chemical Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-6

Toxic Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-13

Asbestos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-13

Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-15

Arsenic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-19

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-20

Chapter 6—Housing Structure

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1

New Housing Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1

Old Housing Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-6

Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-8

Vapor Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-10

Crawl Space Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-10

Vapor Barriers for Concrete Slab Homes . . . . . . . . . . . . . . . . . . . . . . . . . . .6-10

Wall and Ceiling Vapors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-10

House Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-10

Foundation Sills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-10

Flooring Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-10

Studs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-11

Interior Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-11

Stairways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-12

Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-12

Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-13

Roof Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Rafters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Collar Beam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Purlin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Ridge Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Hip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Roof Sheathing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Dormer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

2 Contents
Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Asphalt Shingle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

EPDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-15

Asphalt Built-up Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Coal Tar Pitch Built-up Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Slate Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Tile Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Copper Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Galvanized Iron Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Wood Shingle Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Roof Flashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Gutters and Leaders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Exterior Walls and Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16

Putting It All Together . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-17

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-21

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-22

Chapter 7—Environmental Barriers

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-1

Roof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-2

Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3

Siding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3

Fiber Cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-4

Brick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-4

Stucco . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-4

Vinyl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-5

Asbestos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-5

Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-5

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-6

Chapter 8—Rural Water Supplies and Water-quality Issues

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-1

Water Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-1

Source Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2

Well Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3

Sanitary Design and Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4

Pump Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4

Dug and Drilled Wells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4

Springs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-6

Cisterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-6

Disinfection of Water Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-7

Chlorine Carrier Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9

Routine Water Chlorination (Simple) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9

Well Water Shock Chlorination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9

Backflow, Back-siphonage, and Other Water Quality Problems . . . . . . . . . . . . . . .8-9

Backflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9

Back-siphonage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-10

Other Water Quality Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-10

Healthy Housing Reference Manual 3
Protecting the Groundwater Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-10

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-11

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-12

Chapter 9—Plumbing

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1

Elements of a Plumbing System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1

Water Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1

Hot and Cold Water Main Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-3

Water Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-7

Drainage System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-8

Corrosion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-13

Water Conservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-13

Putting It All Together . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-14

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-15

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-16

Chapter 10—On-site Wastewater Treatment

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-1

Treatment of Human Waste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-1

On-site Wastewater Treatment Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3

Septic Tank Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3

Alternative Septic Tank Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-6

Maintaining the On-site Wastewater Treatment Systems . . . . . . . . . . . . . . . . . . .10-8

Symptoms of Septic System Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-9

Septic Tank Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-9

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-11

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-12

Chapter 11—Electricity

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-1

Flow of Electric Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-2

Electric Service Entrance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-3

Service Drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-3

Underground Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-4

Electric Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-4

Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-4

Two- or Three-wire Electric Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-6

Residential Wiring Adequacy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-6

Wire Sizes and Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7

Reducing Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7

Wire Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7

Wire Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-8

Types of Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-8

Flexible Cords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-9

The Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-9

The Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-9

4 Contents
Safety Suggestions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-9

Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-10

Open Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-10

Concealed Knob and Tube Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-10

Electric Service Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-10

Over-Current Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-10

Circuit Breakers (Fuseless Service Panels) . . . . . . . . . . . . . . . . . . . . . . . . . .11-11

Ground Fault Circuit Interrupters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-11

Arc-fault Circuit Interrupters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-12

Fused Ampere Service Panel (Fuse Box) . . . . . . . . . . . . . . . . . . . . . . . . . . .11-12

Electric Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-13

Outlet Switches and Junction Boxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-13

Grounding Outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-13

Polarized Plugs and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-14

Common Electrical Violations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-14

Excessive or Faulty Fusing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-15

Cords Run Through Walls or Doorways and Hanging Cords or Wires . . . . .11-15

Temporary Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-16

Excessively Long Extension Cords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-16

Dead or Dummy Outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-16

Aluminum Wiring Inside the Home . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-16

Inspection Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-16

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-17

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-17

Chapter 12—Heating, Air Conditioning, and Ventilating

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-1

Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-4

Standard Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-4

Central Heating Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-7

Space Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-12

Hydronic Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-14

Direct Vent Wall Furnaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-15

Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-15

Air Conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-15

Circulation Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-16

Evaporation Coolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-16

Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-17

Chimneys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-17

Fireplaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-18

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-19

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-19

Chapter 13—Energy Efficiency

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-1

Energy Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-1

R-values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-1

Healthy Housing Reference Manual 5
Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-2

Ridge Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-3

Fan-powered Attic Ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-3

White Roof Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-3

Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-3

Wall Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-4

Floor Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-4

Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-5

Hot Water Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-7

Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-7

Caulking and Weather-stripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-7

Replacing Window Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-7

Tinted Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-8

Reducing Heat Loss and Condensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-8

Glazing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-8

Layering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-8

Other Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-9

Solar Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-9

Active Solar Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-9

Passive Solar Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-10

Conducting an Energy Audit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-10

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-11

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-11

Chapter 14—Residential Swimming Pools and Spas

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-1

Child-proofing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-1

Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-2

Public Health Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-2

Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-3

Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-3

Water Testing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-3

Disinfection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-4

Content Turnover Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-4

Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-5

High-rate Sand Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-5

Cartridge Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-5

Diatomaceous Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-5

Filter Loading Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-5

Disinfectants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-5

Effect of pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-6

Chlorine Disinfectants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-6

Pool Water Hardness and Alkalinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-8

Liquid Chemical Feeders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-9

Positive Displacement Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-9

Erosion and Flow-through Disinfectant Feeders . . . . . . . . . . . . . . . . . . . . .14-10

Spas and Hot Tubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-10

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-11

Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-11

6 Contents
Chapter 1—Housing History and Purpose

Figure 1.1. Conditions in the Tenements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

Figure 1.2. Levittown, New York . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

Chapter 2—Basic Principles of Healthy Housing 

Figure 2.1. Circa 1890 Icebox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

Figure 2.2. Smoke Alarm Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

Chapter 3—Housing Regulations

Figure 3.1. Example of a Floor Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5

Figure 3.2. Example of an Angle of Light Obstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5

Chapter 4—Disease Vectors and Pests

Figure 4.1. Field Identification of Domestic Rodents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2

Figure 4.2. Norway Rat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2

Figure 4.3. Roof Rat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2

Figure 4.4. Signs of Rodent Infestation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3

Figure 4.5. Rodent Prevention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4

Figure 4.6. Live Trap for Rats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4

Figure 4.7. Kill Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4

Figure 4.8. American, Oriental, German, and Brown-banded Cockroaches . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4.9. American Cockroaches, Various Stages and Ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4.10. Oriental Cockroaches, Various Stages and Ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4.11. German Cockroaches, Various Stages and Ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4.12. Brown-banded Cockroaches, Various Stages and Ages . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4.13. Wood Cockroach, Adult Male . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

Figure 4.14. Reported Human Plague Cases (1970–1997) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-6

Figure 4.15. Flea Life Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-6

Figure 4.16. Housefly (Musca domestica) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-7

Figure 4.17. Life Cycle of the Fly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-8

Figure 4.18. Termite Tube Extending From Ground to Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-9

Figure 4.19. Termite Mud Shelter Tube Constructed Over A Brick Foundation . . . . . . . . . . . . . . . . . . .4-9

Figure 4.20. Differences Between Ants and Termites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-9

Figure 4.21. Life Cycle of the Subterranean Termite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-10

Figure 4.22. Subterranean Termite Risk in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-11

Figure 4.23. Typical Points of Attack by Termites in the Home . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-12

Figure 4.24. Construction Techniques That Discourage Termite Attacks . . . . . . . . . . . . . . . . . . . . . . . . .4-14

Figure 4.25. Fire Ants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-14

Figure 4.26. Range Expansion of Red Imported Fire Ants (RIFA) in the United States, 1918–1998 . . . .4-15

Figure 4.27. Fire Ant Mound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-15

Chapter 5—Indoor Air Pollutants and Toxic Materials

Figure 5.1. Mold Growth in the Home . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-7

Figure 5.2. Home Carbon Monoxide Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-7

Figure 5.3. Environmental Tobacco Smoke and Children’s Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . .5-8

Figure 5.4. Wood Products Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-10

Figure 5.5. EPA Map of Radon Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-10

Figure 5.6. Radon Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-11

Figure 5.7. Home Radon Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-12

List of Figures

Healthy Housing Reference Manual 7
Figure 5.9. Radon-resistant Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-12

Figure 5.10. Arsenic Label. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-19

Chapter 6—Housing Structure

Figure 6.1. Housing Structure Terminology, Typical House Built Today . . . . . . . . . . . . . . . . .6-1

Figure 6.2. Housing Structure Terminology, Typical House Built Between 1950 and 1980 . . . .6-6

Figure 6.3. Foundation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-9

Figure 6.4. Foundation Cracks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-9

Figure 6.5. Interior Stairway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-12

Figure 6.6. Classifications of Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-12

Figure 6.7. Three-dimensional View of a Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-13

Figure 6.8. Window Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-13

Figure 6.9. Wall Framing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-17

Chapter 7—Environmental Barriers

Figure 7.1. Sources of Moisture and Air Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-1

Figure 7.2. Blown Attic Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3

Figure 7.3. Depth of Attic Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3

Figure 7.4. Attic Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3

Figure 7.5. Brick Structural Defect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-4

Figure 7.6. Corrosion in Piping Resulting From Galvanic Response . . . . . . . . . . . . . . . . . . . .7-5

Chapter 8—Rural Water Supplies

Figure 8.1. U.S. Water Supply by Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-1

Figure 8.2. Cross Section of a Driven Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3

Figure 8.3. Well Seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4

Figure 8.4. Converted Dug Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4

Figure 8.5. Recapped and Sealed Dug Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-5

Figure 8.6. Drilled Well. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-5

Figure 8.7. Typical Dug Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-5

Figure 8.8. Sewage in Drainage Ditch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-6

Figure 8.9. Drilled Well. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-6

Figure 8.10. Spring Box. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-6

Chapter 9—Plumbing

Figure 9.1. Typical Home Water System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1

Figure 9.2. House Service Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-2

Figure 9.3. Gas Water Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-7

Figure 9.4. Temperature-pressure Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-8

Figure 9.5. Branch Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-10

Figure 9.6. P-trap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-10

Figure 9.7. Types of S-traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-10

Figure 9.8. Trap Seal: (a) Seal Intact; (b) Fixture Draining; (c) Loss of Gas Seal . . . . . . . . . . . .9-10

Figure 9.9. Loss of Trap Seal in Lavatory Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-11

Figure 9.10. Back-to-back Venting (Toilet). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-11

Figure 9.11. Back-to-back Venting (Sink). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-11

Figure 9.12. Wall-hung Fixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-12

Figure 9.13. Unit Vent Used in Bathtub Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-12

Figure 9.14. Toilet Venting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-12

Figure 9.15. Janitor’s Sink. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-13

Figure 9.16. Common Y-trap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-13

Figure 9.17. Hose Bib With Vacuum Breaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-13

8 List of Figures
Chapter 10—On-site Wastewater Treatment

Figure 10.1. Conventional On-site Septic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-1

Figure 10.2. Straight Pipe Discharge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-2

Figure 10.3. Clear Creek Water Contaminated With Sewage. . . . . . . . . . . . . . . . . . . . . . . . . .10-2

Figure 10.4. Septic Tank System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3

Figure 10.5. Septic Tank. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-4

Figure 10.6. On-site Sewage Disposal System Site Evaluation Form . . . . . . . . . . . . . . . . . . . .10-5

Figure 10.7. Cross-section of an Absorption Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-5

Figure 10.8. Mound System Cutaway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-7

Figure 10.9. Low Pressure On-site System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-7

Figure 10.10. Plant-rock Filter System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-8

Figure 10.11. Sludge and Scum in Multicompartment Septic Tank . . . . . . . . . . . . . . . . . . . . . .10-10

Chapter 11—Electricity

Figure 11.1. Utility Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-3

Figure 11.2. Entrance Head. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-3

Figure 11.3. Armored Cable Service Entrance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-4

Figure 11.4. Breakers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-4

Figure 11.5. Thin-wall Conduit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-4

Figure 11.6. Electric Meter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-5

Figure 11.7. Typical Service Entrance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-5

Figure 11.8. Grounding Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-6

Figure 11.9. Grounding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-6

Figure 11.10. Three-wire Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7

Figure 11.11. Two-wire Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7

Figure 11.12. Wire Markings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-8

Figure 11.13. Armored Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-9

Figure 11.14. 200-Amp Service Box. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-11

Figure 11.15. External Power Shutoff and Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-11

Figure 11.16. Ground Fault Circuit Interruptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-12

Figure 11.17. Arc Interrupter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-12

Figure 11.18. Types of Fuses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-13

Figure 11.19. Appliance Ground and Grounded Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-14

Chapter 12—Heating, Air Conditioning, and Ventilating

Figure 12.1. Heat Pump in Cooling Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-5

Figure 12.2. Piping Hookup for Inside Tank Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-6

Figure 12.3. Piping Hookup for Buried Outside Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-6

Figure 12.4. Minimum Clearance for Pipeless Hot Air and Gravity Warm Air Furnace . . . . . .12-7

Figure 12.5. Minimum Clearance for Steam or Hot Water Boiler and Mechanical Warm-air Furnace .12-7

Figure 12.6. Heating Ducts Covered With Asbestos Insulation . . . . . . . . . . . . . . . . . . . . . . . .12-7

Figure 12.7. Typical Underfeed Coal Stoker Installation in Small Boilers . . . . . . . . . . . . . . . . .12-8

Figure 12.8. Cutaway View of Typical High-pressure Gun Burner . . . . . . . . . . . . . . . . . . . . . .12-9

Figure 12.9. Gas-fired Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-9

Figure 12.10. Typical Gravity One-pipe Heating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-10

Figure 12.11. One-pipe Gravity Water Heating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11

Figure 12.12. Two-pipe Gravity Water Heating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11

Figure 12.13. Warm-air Convection Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11

Figure 12.14. Cross-sectional View of Building Showing Forced-warm-air Heating System . . . .12-12

Figure 12.15. Perforated-sleeve Burner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-13

Figure 12.16. Condition of Burner Flame With Different Rates of Fuel Flow . . . . . . . . . . . . . .12-13

Figure 12.17. Wall and Ceiling Clearance Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-14

Healthy Housing Reference Manual 9
Figure 12.18. Draft in Relation to Height of Chimney . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-14

Figure 12.19. Location and Operation of Typical Backdraft Diverter . . . . . . . . . . . . . . . . . . . .12-15

Figure 12.20. Split-system Air Conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-16

Figure 12.21. External Air-conditioning Condenser Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-16

Figure 12.22. Chimney Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-17

Figure 12.23. Fireplace Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-18

Chapter 13—Energy Efficiency

Figure 13.1. Roof Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-3

Figure 13.2. Potential Effects of Radiant Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-4

Figure 13.3. Common Floor Insulation Flaws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-5

Figure 13.4. Insulation Cavity Fill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-6

Figure 13.5. Solar Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-9

Chapter 14—Residential Swimming Pools and Spas

Figure 14.1. Pool Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-2

Figure 14.2. Typical Home Pool Equipment System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-5

10 List of Figures
Healthy Housing Reference Manual 11

Chapter 8—Rural Water Supplies and Water-quality Issues

Table 8.1. Recommended Minimum Distance Between Well and Pollution Sources . . . . . . . .8-2

Table 8.2. Types of Wells for Accessing Groundwater, Well Depths, and Diameters . . . . . . . .8-3

Table 8.3. Disinfection Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-7

Table 8.4. Chlorination Guide for Specific Water Conditions . . . . . . . . . . . . . . . . . . . . . . . .8-8

Table 8.5. Preparing a 200-ppm Chlorine Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9

Table 8.6. Analyzing and Correcting Water Quality Problems . . . . . . . . . . . . . . . . . . . . . . . .8-11

Chapter 9—Plumbing

Table 9.1. Fixture Unit Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-9

Table 9.2. Sanitary House Drain Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-9

Table 9.3. Minimum Fixture Service Pipe Diameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-12

Chapter 10—On-site Wastewater Treatment

Table 10.1. Mound System Advantages and Disadvantages . . . . . . . . . . . . . . . . . . . . . . . . . .10-6

Table 10.2. Low-pressure Pipe Systems Advantages and Disadvantages . . . . . . . . . . . . . . . . . .10-7

Table 10.3. Plant Rock Filter System Advantages and Disadvantages . . . . . . . . . . . . . . . . . . .10-8

Table 10.4. Septic Tank System Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-10

Chapter 13—Energy Efficiency

Table 13.1. Cost-effective Insulation R-values for Existing Homes . . . . . . . . . . . . . . . . . . . . .13-2

Table 13.2. R-values of Roof Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-3

Table 13.3. Floor Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-5

Chapter 14—Residential Swimming Pools and Spas

Table 14.1. Pool Water Quality Problem Solving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-7

Table 14.2. pH Effect on Chlorine Disinfection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-8

Table 14.3. Chlorine Use in Swimming Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-8

Table 14.4. Swimming Pool Operating Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-9

Table 14.5. Spa and Hot Tub Operating Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-11

List of Tables
12 List of Tables
Healthy Housing Reference Manual 13

Housing quality is key to the public’s health. Translating that simple axiom into action is the topic of this book.

In the 30 years since the first edition was published, the nation’s understanding of how specific housing conditions are related to disease and injury has matured and deepened. This new edition will enable public health

and housing professionals to grasp our shared responsibility to ensure that our housing stock is safe, decent, affordable, and healthy for our citizens, especially those who are particularly vulnerable and who spend more time in the

home, such as children and the elderly.

The Centers for Disease Control and Prevention and the U.S. Department of Housing and Urban Development

(HUD) have worked together with many others to discover the ways to eliminate substandard housing conditions that

harm health. For example, the advances in combating water borne diseases was possible, in part, through standardization of indoor plumbing and sewage, and the institution of federal, state and local regulations and codes. Childhood

lead poisoning has been dramatically reduced, in part, through the elimination of residential lead-based paint hazards.

Other advances have been made to protect people from carbon monoxide poisoning, falls, safety hazards, electrocution, and many other risks. 

However, more must be done to control existing conditions and to understand emerging threats that remain poorly

understood. For example, nearly 18 million Americans live with the health threat of contaminated drinking water

supplies, especially in rural areas where on-site wastewater systems are prevalent. Despite progress, thousands of children still face the threat of lead poisoning from residential lead paint hazards. The increase in asthma in recent

decades and its relationship to housing conditions such as excess moisture, mold, settled dust allergens and ventilation

remains the subject of intense research. The impact of energy conservation measures on the home environment is still

unfolding. Simple affordable construction techniques and materials that minimize moisture problems and indoor air

pollution, improve ventilation, and promote durability and efficiency continue to be uncovered.

A properly constructed and maintained home is nearly timeless in its usefulness. A home is often the biggest single

investment people make. This manual will help to ensure that the investment is a sound one that promotes healthy

and safe living.

Home rehabilitation has increased significantly in the last few years and HUD has prepared a nine-part series, The

Rehab Guide, that can assist both residents and contractors in the rehabilitation process. For additional information,

go to http://www.huduser.org/publications/destech/rehabgui.html. 

Preface
14 Preface
We acknowledge the suggestions, assistance, and review of numerous individuals and organizations that went

into the original and current versions of this manual. The revisions to this manual were made by a team of

environmental health, housing, and public health professionals led by Professor Joe Beck, Dr. Darryl

Barnett, Dr. Gary Brown, Dr. Carolyn Harvey, Professor Worley Johnson, Dr. Steve Konkel, and Professor Charles

Treser.

Individuals from the following organizations were involved in the various drafts of this manual:

• Department of Housing and Urban Development (HUD), Office of Healthy Homes and Lead Hazard

Control;

• U.S. Department of Health and Human Services (HHS), Centers for Disease Control and Prevention (CDC),

National Center for Environmental Health (NCEH); 

• National Healthy Homes Training Center and Network; 

• National Association of Housing and Redevelopment Officials;

• Department of Building, Housing and Zoning (Allentown, Pennsylvania); 

• Code Enforcement Associates (East Orange, New Jersey); 

• Eastern Kentucky University (Richmond, Kentucky); 

• University of Washington; Seattle (Washington); and

• Battelle Memorial Institute (Columbus, Ohio). 

Specifically, our gratitude goes to the following reviewers:

• Dr. David Jacobs, Martin Nee, and Dr. Peter Ashley, HUD; 

• Pat Bohan, East Central University; 

• James Larue, The House Mender Inc.; 

• Ellen Tohn, ERT Associates; 

• Dr. Stephen Margolis, Emory University; and 

• Joseph Ponessa and Rebecca Morley, Healthy Homes Training Center. 

A special thank-you for assistance from Carolyn Case-Compton, Habitat for Humanity, 123 East Main Street,

Morehead, Kentucky. Pictures of a home under construction are courtesy of Habitat for Humanity and John King,

home builder and instructor, Rowan County Technical College, Morehead, Kentucky; and Don W. Johnson, building

photographer of Habitat for Humanity.

In addition, a special thank you to CAPT Craig Shepherd and CAPT Michael Herring, Commissioned Corps, U.S.

Public Health Service, CDC/NCEH/Environmental Health Services Branch for their research and review during the

editing of this manual. Special thanks to Pamela S. Wigington and Joey L. Johnson for their hard work preparing this

manual for publication and to Teresa M. Sims for Web publication.

Acknowledgments

Healthy Housing Reference Manual 15
16 Acknowledgments
Healthy Housing Reference Manual 17

ABS acrylonitrile-butadiene-styrene

ADA Americans with Disabilities Act

AGA American Gas Association

ALA American Lung Association

ANSI American National Standards Institute

APHA American Public Health Association

ASME American Society of Mechanical Engineers

ASSE American Society of Structural Engineers

ASTM American Society for Testing Materials

ATSDR Agency for Toxic Substances and Disease Registry

AWG American Wire Gauge

AWWA American Waters Works Association

BTU British thermal unit

CDC Centers for Disease Control and Prevention

CFR Code of Federal Regulations

CGA Canadian Gas Association

CO carbon monoxide

CPR cardiopulmonary resuscitation

CPSC Consumer Product Safety Commission

CSIA Chimney Safety Institute of America

DDT dichlorodiphenyltrichlorethane

DE diatomaceous earth

DPD N,N-diethyl-p-phenylene diamine

DWV drain, waste, and vent

EIFS exterior insulation and finish system

EPA U.S. Environmental Protection Agency

EPDM ethylene propylene dieneterpolymer

ETS environmental tobacco smoke

FHA Federal Housing Administration

FM Factory Mutual

GFCI ground fault circuit interrupter

HEPA high-efficiency particulate air

HHS Health and Human Services, U.S. Department of

HSC Home Safety Council

HUD Housing and Urban Development, U.S. Department of

HVAC heating, ventilating and air conditioning

IAPMO International Association of Plumbing and Mechanical Officials

ICC International Code Council

IPM integrated pest management

ISO International Standard Organization

kg kilogram

LPP low-pressure pipe

MPMH Military Pest Management Handbook

MSS Mechanical Standardization Society of the Valve and Fitting Industry

NCEH National Center for Environmental Health

NCI National Cancer Institute

NIA National Institute on Aging

NSF National Science Foundation

NTU nephelometric turbidity unit

Abbreviations and Acronyms
18 Abbreviations and Acronyms

ODTS organic dust toxic syndrome

OSHA Occupational Safety and Health Administration

PEX cross-formulated polyethylene

POTW publicly owned treatment works

ppm parts per million

psi pound per square inch

PVC polyvinyl chloride

PW potable water

RIFA red imported fire ant

SDWA Safe Drinking Water Act

SEER seasonal energy efficiency ratio

T&P temperature-pressure

TSP trisodium phosphate

UF urea-formaldehyde

UL Underwriters Laboratories

USCB U.S. Census Bureau 

USDA U.S. Department of Agriculture

USFA U.S. Fire Administration

USGS U.S. Geological Survey

USHA United States Housing Authority

VA Veteran’s Administration

VOC volatile organic compound

XRF X-ray fluorescence
Healthy Housing Reference Manual 19

Accessory building or structure: a detached building or structure in a secondary or subordinate capacity from the

main or principal building or structure on the same premises.

Appropriate authority/Authority having jurisdiction (AHJ): a person within the governmental structure of the

corporate unit who is charged with the administration of the appropriate code.

Ashes: the residue from burning combustible materials.

Attic: any story or floor of a building situated wholly or partly within the roof, and so designed, arranged, or built to

be used for business, storage, or habitation.

Basement: the lowest story of a building, below the main floor and wholly or partially lower than the surface of the ground.

Building: a fixed construction with walls, foundation, and roof, such as a house, factory, or garage.

Bulk container: any metal garbage, rubbish, or refuse container having a capacity of 2 cubic yards or greater and which is

equipped with fittings for hydraulic or mechanical emptying, unloading, or removal.

Central heating system: a single system supplying heat to one or more dwelling unit(s) or more than one rooming unit.

Chimney: a vertical masonry shaft of reinforced concrete, or other approved noncombustible, heat-resisting material

enclosing one or more flues, for the purpose of removing products of combustion from solid, liquid, or gaseous fuel.

Dilapidated: in a state of disrepair or ruin and no longer adequate for the purpose or use for which it was originally intended.

Dormitory: a building or a group of rooms in a building used for institutional living and sleeping purposes by four or

more persons.

Dwelling: any enclosed space wholly or partly used or intended to be used for living, sleeping, cooking, and eating.

(Temporary housing, as hereinafter defined, shall not be classified as a dwelling.) Industrialized housing and modular

construction that conform to nationally accepted industry standards and are used or intended for use for living,

sleeping, cooking, and eating purposes shall be classified as dwellings.

Dwelling unit: a room or group of rooms located within a dwelling forming a single habitable unit with facilities used

or intended to be used by a single family for living, sleeping, cooking, and eating.

Egress: arrangements and openings to assure a safe means of exit from buildings.

Extermination: the control and elimination of insects, rodents, or other pests by eliminating their harborage places;

by removing or making inaccessible materials that may serve as their food; by poisoning, spraying, fumigating,

trapping, or any other recognized and legal pest elimination methods approved by the local or state authority having

such administrative authority. Extermination is one of the components of integrated pest management.

Fair market value: a price at which both buyers and sellers will do business.

Family: one or more individuals living together and sharing common living, sleeping, cooking, and eating facilities

(See also Household).

Definitions
Flush toilet: a toilet bowl that can be flushed with water supplied under pressure and that is equipped with a watersealed trap above the floor level.

Garbage: animal and vegetable waste resulting from handling, preparation, cooking, serving, and nonconsumption of food.

Grade: the finished ground level adjacent to a required window.

Guest: an individual who shares a dwelling unit in a nonpermanent status for not more than 30 days.

Habitable room: a room or enclosed floor space used or intended to be used for living, sleeping, cooking or eating

purposes, excluding bathrooms, laundries, furnace rooms, pantries, kitchenettes and utility rooms of less than

50 square feet of floor space, foyers, or communicating corridors, stairways, closets, storage spaces, workshops, and hobby

and recreation areas.

Health officer: the legally designated health authority of the jurisdiction or that person’s authorized representative.

Heated water: water heated to a temperature of not less than 120°F–130°F (49°C–54°C) at the outlet.

Heating device: all furnaces, unit heaters, domestic incinerators, cooking and heating stoves and ranges, and other similar devices.

Household: one or more individuals living together in a single dwelling unit and sharing common living, sleeping,

cooking, and eating facilities (see also Family).

Infestation: the presence within or around a dwelling of any insects, rodents, or other pests.

Integrated pest management: a coordinated approach to managing roaches, rodents, mosquitoes, and other pests that

combines inspection, monitoring, treatment, and evaluation, with special emphasis on the decreased use of toxic agents. 

Kitchen: any room used for the storage and preparation of foods and containing the following equipment: sink or

other device for dishwashing, stove or other device for cooking, refrigerator or other device for cold storage of food,

cabinets or shelves for storage of equipment and utensils, and counter or table for food preparation.

Kitchenette: a small kitchen or an alcove containing cooking facilities.

Lead-based paint: any paint or coating with lead content equal to or greater than 1 milligram per square centimeter,

or 0.5% by weight. 

Multiple dwelling: any dwelling containing more than two dwelling units.

Occupant: any individual, over 1 year of age, living, sleeping, cooking, or eating in or having possession of a dwelling

unit or a rooming unit; except that in dwelling units a guest shall not be considered an occupant.

Operator: any person who has charge, care, control or management of a building, or part thereof, in which dwelling

units or rooming units are let.

Ordinary summer conditions: a temperature 10°F (-12°C) below the highest recorded temperature in the locality for

the prior 10-year period.

Ordinary winter conditions: mean a temperature 15°F (-9.4°C) above the lowest recorded temperature in the locality

for the prior 10-year period.

20 Definitions
Owner: any person who alone, jointly, or severally with others (a) shall have legal title to any premises, dwelling, or

dwelling unit, with or without accompanying actual possession thereof, or (b) shall have charge, care or control of any

premises, dwelling, or dwelling unit, as owner or agent of the owner, or as executor, administrator, trustee, or guardian

of the estate of the owner.

Permissible occupancy: the maximum number of individuals permitted to reside in a dwelling unit, rooming unit, or dormitory.

Person: any individual, firm, corporation, association, partnership, cooperative, or government agency.

Plumbing: all of the following supplied facilities and equipment: gas pipes, gas burning equipment, water pipes,

garbage disposal units, waste pipes, toilets, sinks, installed dishwashers, bathtubs, shower baths, installed clothes

washing machines, catch basins, drains, vents, and similarly supplied fixtures, and the installation thereof, together with all

connections to water, sewer, or gas lines.

Privacy: the existence of conditions which will permit an individual or individuals to carry out an activity commenced

without interruption or interference, either by sight or sound by unwanted individuals.

Rat harborage: any conditions or place where rats can live, nest or seek shelter.

Ratproofing: a form of construction that will prevent the entry or exit of rats to or from a given space or building, or

from gaining access to food, water, or harborage. It consists of the closing and keeping closed of every opening in

foundations, basements, cellars, exterior and interior walls, ground or first floors, roofs, sidewalk gratings, sidewalk

openings, and other places that may be reached and entered by rats by climbing, burrowing, or other methods, by the

use of materials impervious to rat gnawing and other methods approved by the appropriate authority.

Refuse: leftover and discarded organic and nonorganic solids (except body wastes), including garbage, rubbish, ashes, and dead animals.

Refuse container: a watertight container that is constructed of metal, or other durable material impervious to rodents,

that is capable of being serviced without creating unsanitary conditions, or such other containers as have been

approved by the appropriate authority (see also Appropriate Authority). Openings into the container, such as covers and

doors, shall be tight fitting.

Rooming house: any dwelling other than a hotel or motel or that part of any dwelling containing one or more

rooming units, or one or more dormitory rooms, and in which persons either individually or as families are housed with or

without meals being provided.

Rooming unit: any room or group of rooms forming a single habitable unit used or intended to be used for living

and sleeping, but not for cooking purposes.

Rubbish: nonputrescible solid wastes (excluding ashes) consisting of either: (a) combustible wastes such as paper,

cardboard, plastic containers, yard clippings and wood; or (b) noncombustible wastes such as cans, glass, and crockery. 

Safety: the condition of being reasonably free from danger and hazards that may cause accidents or disease.

Space heater: a self-contained heating appliance of either the convection type or the radiant type and intended

primarily to heat only a limited space or area such as one room or two adjoining rooms. 

Supplied: paid for, furnished by, provided by, or under the control of the owner, operator or agent.

System: the dynamic interrelationship of components designed to enact a vision.

Healthy Housing Reference Manual 21
Systems theory: The concept proposed to promote the dynamic interrelationship of activities designed to accomplish

a unified system.

Temporary housing: any tent, trailer, mobile home, or other structure used for human shelter that is designed to be

transportable and which is not attached to the ground, to another structure, or to any utility system on the same premises for

more than 30 consecutive days.

Toxic substance: any chemical product applied on the surface of or incorporated into any structural or decorative

material, or any other chemical, biologic, or physical agent in the home environment or its immediate surroundings,

which constitutes a potential hazard to human health at acute or chronic exposure levels.

Variance: a difference between that which is required or specified and that which is permitted. 

22 Definitions
Healthy Housing Reference Manual 23

In addition to the standards and organizations listed in this section, the U.S. Justice Department enforces the

requirements of the Americans with Disabilities Act (ADA) (http://www.ada.gov) and assures that products fully

comply with the provisions of the act to ensure equal access for physically challenged users.

ABPA The American Backflow Prevention Association, http://abpa.org

Develops cross-connections; ABPA is an organization whose members have a common interest in 

protecting drinking water from contamination. 

ACI American Concrete Institute, http://www.concrete.org/general/home.asp

Has produced more than 400 technical documents, reports, guides, specifications, and codes for the best use of 

concrete. ACI conducts more than 125 educational seminars each year and has 13 certification programs 

for concrete practitioners, as well as a scholarship program to promote careers in the industry.

AGA American Gas Association, http://www.aga.org

Develops standards, tests, and qualifies products used in gas lines and gas appliance installations.

AGC Associated General Contractors of America, http://www.agc.org

Is dedicated to improving the construction industry by educating the industry to employ the finest skills, 

promoting use of the latest technology and advocating building the best quality projects for owners—

public and private. 

AMSA Association of Metropolitan Sewerage Agencies, http://www.amsa-cleanwater.org

Represents the interests of the country’s wastewater treatment agencies. 

ANSI American National Standards Institute, http://www.ansi.org

Coordinates work among U.S. standards writing groups. Works in conjunction with other groups such as 

ISO, ASME, and ASTM.

ARI Air-Conditioning and Refrigeration Institute, http://www.ari.org

Provides information about the 21st Century Research (21-CR) initiative, a private-public sector research

collaboration of the heating, ventilation, air-conditioning, and refrigeration industry, with a focus on 

energy conservation, indoor environmental quality, and environmental protection. 

ASCE American Society of Civil Engineers, http://www.asce.org

Provides essential value to its members, careers, partners, and the public by developing leadership, 

advancing technology, advocating lifelong learning, and promoting the profession.

ASHI The American Society of Home Inspectors, http://www.ashi.org

Is a source of information about the home inspection profession. 

ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, http://www.ashrae.org

Writes standards and guidelines that include uniform methods of testing for rating purposes, describe 

recommended practices in designing and installing equipment and provide other information to guide the 

industry. ASHRAE has more than 80 active standards and guideline project committees, addressing such

broad areas as indoor air quality, thermal comfort, energy conservation in buildings, reducing refrigerant 

emissions, and the designation and safety classification of refrigerants.

Standards and Organizations
24 Standards and Organizations

ASME The American Society of Mechanical Engineers, http://www.asme.org

Develops standards for materials and testing as well as finished products. 

ASSE American Society of Sanitary Engineering, http://www.asse.org

Develops standards and qualifies products for plumbing and sanitary installations.

ASTM American Society for Testing and Materials, http://www.astm.org

Is one of the largest voluntary standards development organizations in the world-a trusted source for 

technical standards for materials, products, systems, and services. 

AWWA American Water Works Association, http://www.awwa.org

Promotes public health through improvement of the quality of water and develops standards for valves, fittings, and other 

equipment.

CGA Canadian Gas Association, http://www.cga.ca

Develops standards, tests, and qualifies products used in gas lines and gas appliance installations.

CPSC U.S Consumer Product Safety Commission, http://www.cpsc.gov

Protects the public from unreasonable risks for serious injury or death from more than 15,000 types of 

consumer products. CPSC is committed to protecting consumers and families from products that pose a 

fire, electrical, chemical, or mechanical hazard or can injure children. 

CRBT Center for Resourceful Building Technology, http://www.crbt.org

Contains the online Guide to Resource-Efficient Building Elements, which provides information about 

environmentally efficient construction materials, including foundations, wall systems, panels, insulation, 

siding, roofing, doors, windows, interior finishing, and floor coverings. 

EPA U.S. Environmental Protection Agency, http://www.epa.gov

Protects human health and the environment. 

FM Factory Mutual, http://fmglobal.com

Develops standards and qualifies products for use by the general public and develops standards for materials, 

products, systems, and services.

HFHI Habitat for Humanity International, http://www.habitat.org

Is a nonprofit, ecumenical Christian housing ministry. HFHI seeks to eliminate poverty housing and 

homelessness from the world, and to make decent shelter a matter of conscience and action.

HUD U.S. Department of Housing and Urban Development, http://www.hud.gov

As part of the HUD efforts toward eliminating childhood lead poisoning, the Office of Healthy Homes 

and Lead Hazard Control is sharing local lead ordinances and regulations that have proven effective in 

helping communities deal with lead-based paint hazards. Also, the design and construction of 

manufactured housing are regulated by the federal government and must comply with HUD’s 

Manufactured Home Construction and Safety Standards. Modular and panelized construction must 

comply with model or local building codes.

IAPMO International Association of Plumbing and Mechanical Officials, http://www.iapmo.org

Developed and maintains the Uniform Plumbing Code and the Uniform Mechanical Code. 
ICBO The Uniform Building Code (UBC)/International Conference of Building Officials, 

http://www.iccsafe.org

Is the most widely adopted model building code in the world and is a proven document meeting the 

needs of government units charged with enforcement of building regulation. Published triennially, the 

UBC provides complete regulations covering all major aspects of building design and construction relating 

to fire and life safety and structural safety. The requirements reflect the latest technologic advances available 

in the building and fire- and life-safety industry.

ICC International Code Council, http://www.iccsafe.org

Produces the most widely adopted and enforced building safety codes in the United States (I-Codes). 

International Residential Code (IRC) 2003 has been adopted by many states, jurisdictions, and localities. 

IRC also references several industry standards such as ACI 318, ASCE 7, ASTM, and ANSI standards that 

cover specific load, load combinations, design methods, and material specifications.

ISO International Standard Organization, http://www.iso.org

Provides internationally recognized certification for manufacturers that comply with high standards of 

quality control, developed standards ISO-9000 through ISO-9004, and qualifies and lists products suitable for 

use in plumbing installations.

MSS Manufacturers Standardization Society of the Valve and Fittings Industry, Inc., http://www.mss-hq.com

Develops technical codes and standards for the valve and fitting industry.

NACHI The National Association of Certified Home Inspectors, http://www.nachi.org/index.htm

Is the world’s largest, most elite nonprofit inspection association. 

NAHB National Association of Home Builders, http://www.nahb.org

Is a trade association representing more than 220,000 residential home building and remodeling industry 

members. NAHB is affiliated with more than 800 state and local home builders associations around the 

country. NAHB urges codes and standards development and application that protects public health and 

safety without cost impacts that decrease affordability and consequently prevent people from moving into

new, healthier, safer homes.

NEC National Electrical Code, http://www.nfpa.org

Protects public safety by establishing requirements for electrical wiring and equipment in virtually all 

buildings. 

NESC National Environmental Services Center, http://www.nesc.wvu.edu/nesc/nesc_about.htm

Is a repository for water, wastewater, solid waste, and environmental training research. 

NFPA National Fire Protection Association, http://www.nfpa.org/index.asp

Develops, publishes, and disseminates more than 300 consensus codes and standards intended to 

minimize the possibility and effects of fire and other risks. 

NOWRA National Onsite Wastewater Recycling Association, http://www.nowra.org

Provides leadership and promotes the onsite wastewater treatment and recycling industry through 

education, training, communication, and quality tools to support excellence in performance. 

NSF National Sanitation Foundation, http://www.nsf.org

Develops standards for equipment, products and services; a nonprofit organization now known as NSF 

International. 

Healthy Housing Reference Manual 25
UL Underwriters Laboratory, http://www.ul.com

Has developed more than 800 Standards for Safety. Millions of products and their components are tested 

to UL’s rigorous safety standards. 

WEF Water Environment Federation, http://www.wef.org

Is a not-for-profit technical and educational organization with members from varied disciplines who work 

toward the WEF vision of preservation and enhancement of the global water environment. The WEF 

network includes water quality professionals from 76 member associations in 30 countries.

26 Standards and Organizations
Healthy Housing Reference Manual 27

The original Basic Housing Inspection manual was published in 1976 by the Center for Disease Control (now

known as the Centers for Disease Control and Prevention). Its Foreword stated: 

The original Basic Housing Inspection manual has been successfully used for several decades by public health and

housing personnel across the United States. Although much has changed in the field of housing construction and

maintenance, and health and safety issues have expanded, the manual continues to have value, especially as it relates to

older housing. 

Many housing deficiencies impact on health and safety. For example, lead-based paint and dust may contribute to

lead poisoning in children; water leakage and mold may contribute to asthma episodes; improper use and storage of

pesticides may result in unintentional poisoning; and lack of working smoke, ionization, and carbon monoxide alarms may

cause serious injury and death.

Government agencies have been very responsive to “healthy homes” issues. The U.S. Department of Housing and

Urban Development (HUD) created an office with an exclusive focus on healthy homes. In 2003, CDC joined HUD

in the effort to improve housing conditions through the training of environmental health practitioners, public health

nurses, housing specialists, and others who have interest and responsibility for creating healthy homes.

The revised Basic Housing Inspection manual, renamed the Healthy Housing Reference Manual, responds to the

enormous changes that have occurred in housing construction methods and materials and to new knowledge related

to the impact of housing on health and safety. New chapters have been added, making the manual more

comprehensive. For example, an entire chapter is devoted to rural water supplies and on-site wastewater treatment. A

new chapter was added that discusses issues related to residential swimming pools and spas. At over 230 pages, the

comprehensive revised manual is designed primarily as a reference document for public health and housing

professionals who work in government and industry. 

The Healthy Housing Reference Manual contains 14 chapters, each with a specific focus. All chapters contain annotated

references and a listing of sources for additional topic information. A summary of the content of each chapter follows:

Chapter One, Housing History and Purpose, describes the history of dwellings and urbanization and housing

trends during the last century. 

Chapter Two, Basic Principles of Healthy Housing, describes the basic principles of healthy housing and

safety—physiologic needs, psychologic needs, protection against injury and disease—and lays the groundwork

for following chapters. 

Executive Summary

“The growing numbers of new families and the increasing population in the United States have

created a pressing demand for additional housing that is conducive to healthful living. These

demands are increased by the continuing loss of existing housing through deterioration resulting

from age and poor maintenance. Large numbers of communities in the past few years have adopted

housing codes and initiated code enforcement programs to prevent further deterioration of existing

housing units. This growth in housing activities has caused a serious problem for communities in

obtaining qualified personnel to provide the array of housing service needed, such as information,

counseling, technical advice, inspections, and enforcement. As a result many agencies throughout the

country are conducting comprehensive housing inspection training courses. This publication has

been designed to be an integral part of these training sessions.”
28 Executive Summary

Chapter Three, Housing Regulations, reviews the history of housing regulations, followed by a discussion of

zoning, housing, and building codes.

Chapter Four, Disease Vectors and Pests, provides a detailed analysis of disease vectors that have an impact on

residences. It includes information on the management of mice, rats, cockroaches, fleas, flies, termites, and fire ants. 

Chapter Five, Indoor Air Pollution and Toxic Materials, provides information on indoor air pollution, both

biologic and chemical, and to toxic materials in the home, including methods for controlling these hazards. The

impact of cockroaches, dust mites, pets, and mold are discussed. Also included is information about the impact

of carbon monoxide, ozone, tobacco smoke, volatile organic compounds, radon, and pesticides.

Chapter Six, Housing Structure, contains information about “older” housing construction and new construction

materials and methods. The chapter also introduces new terminologies and includes information about

foundations, vapor barriers, house framing, roof framing, exterior walls, and roofs. 

Chapter Seven, Environmental Barriers, provides information on roofing, insulation, and siding materials.

Chapter Eight, Rural Water Supplies and Water-quality Issues, covers issues related to the drilling and proper

maintenance of wells. Research information is provided that indicates that many wells are not properly sealed,

allowing for the leakage of contaminated water into wells during hurricanes and periods of significant flooding.

Chapter Nine, Plumbing, provides information on plumbing standards and how they can be accessed, followed

by a review of the elements of a residential water delivery system, the types of available hot-water heaters,

drainage systems, and methods for water conservation. It also includes a visual synthesis of water system

components during new residential construction.

Chapter Ten, On-site Wastewater Treatment, complements chapter seven by providing information on proper

on-site methods for the treatment of human waste. 

Chapter Eleven, Electricity, expands on information contained in the original manual covering such topics as

breaker systems and polarized plugs and connectors. It also provides a format for the inspection of residential

electrical systems.

Chapter Twelve, Heating, Air Conditioning, and Ventilation, provides information about types of residential

fuels and heating systems, including solar heating and minor sources of heating (e.g., coal-fired, oil-fired, gasfired, and electrical space heaters). Chimney and fireplace safety and the variety of cooling systems are also

discussed.

Chapter Thirteen, Energy Efficiency, discusses energy efficiency, including R-values and their interpretation, roof

ventilation, wall and floor insulation, and door and window energy efficiency systems. It also discusses active and

passive solar systems and provides a methodology for conducting a residential energy audit.

Chapter Fourteen, Residential Swimming Pools and Spas, provides information about child safety, pool and spa

hazards, and diseases. It also provides information on methods for testing and ensuring a safe water system and

on methods for spa and pool disinfection. Further, it covers concerns related to unregulated individual

residential pools and spas.
The quality of housing plays a decisive role in the health status of its occupants. Substandard housing conditions have

been linked to adverse health effects such as childhood lead poisoning, asthma and other respiratory conditions, and

unintentional injuries. This new and revised Healthy Housing Reference Manual is an important reference for anyone

with responsibility and interest in creating and maintaining healthy housing. 

The housing design and construction industry has made great progress in recent years through the development of

new innovative techniques, materials technologies, and products. The HUD Rehab Guide series was developed to

inform the design and construction industry about state-of-the-art materials and innovative practices in housing

rehabilitation. The series focuses on building technologies, materials, components, and techniques rather than on

projects such as adding a new room. The nine volumes each cover a distinct element of housing rehabilitation and

feature breakthrough materials, labor-saving tools, and cost-cutting practices. The nine volumes address foundations;

exterior walls; roofs; windows and doors; partitions, ceilings, floors, and stairs; kitchen and baths; electrical/

electronics; heating, air conditioning, and ventilation; plumbing; and site work. 

Additional information about the series can be found at http://www.huduser.org/publications/destech/rehabgui.html

and http://www.pathnet.org/sp.asp?id=997. This series is an excellent adjunct to the Healthy Housing Reference Manual.

Healthy Housing Reference Manual 29
30 Executive Summary