SACRAMENTO METROPOLITAN AQMD RULES AND REGULATIONS 

March 25, 2010 414-1 

RULE 414, WATER HEATERS, BOILERS AND PROCESS HEATERS RATED LESS THAN 1,000,000 

BTU PER HOUR 

Adopted 08-01-96 

(Amended 03-25-10) 

INDEX

100 GENERAL

101 PURPOSE 

102 APPLICABILITY 

110 EXEMPTION, WATER HEATERS IN RECREATIONAL VEHICLES 

111 EXEMPTION, POOL/SPA HEATERS 

112 EXEMPTION, WATER HEATERS, BOILERS AND PROCESS HEATERS FIRED WITH 

LIQUEFIED PETROLEUM GAS 

200 DEFINITIONS

201 BOILER 

202 BTU 

203 HEAT INPUT 

204 HEAT OUTPUT 

205 LIQUEFIED PETROLEUM GAS 

206 MOBILE HOME WATER HEATER 

207 NATURAL GAS 

208 POOL/SPA HEATER 

209 PROCESS HEATER 

210 RATED HEAT INPUT CAPACITY 

211 RECREATIONAL VEHICLE 

212 WASTE HEAT RECOVERY BOILER 

213 WATER HEATER 

300 STANDARDS

301 EMISSION LIMITS 

302 SELL-THROUGH OF WATER HEATERS, BOILERS AND PROCESS HEATERS 

400 ADMINISTRATIVE REQUIREMENTS 

401 CERTIFICATION REPORT 

402 MANUFACTURERS' LABELING REQUIREMENT 

500 MONITORING AND RECORDKEEPING

501 TESTING PROCEDURE 

502 DURATION OF RECORDS 
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100 GENERAL

101 PURPOSE: To limit the emission of nitrogen oxides (NOx) from water heaters, boilers and 

process heaters. 

102 APPLICABILITY: This rule shall apply to any person who manufactures, distributes, offers 

for sale, sells, or installs any type of water heater (such as tank or tankless/instantaneous), 

boiler or process heater, with a rated heat input capacity less than 1,000,000 British thermal 

units per hour (Btu/hr), fired with gaseous or nongaseous fuels, for use in this District. 

110 EXEMPTION, WATER HEATERS IN RECREATIONAL VEHICLES: This rule shall not 

apply to water heaters used in recreational vehicles. 

111 EXEMPTION, POOL/SPA HEATERS: This rule shall not apply to pool/spa heaters with a 

heat input rating of less than 75,000 Btu/hr. 

112 EXEMPTION, WATER HEATERS, BOILERS AND PROCESS HEATERS FIRED WITH 

LIQUEFIED PETROLEUM GAS: This rule shall not apply to water heaters, boilers and 

process heaters fired with liquefied petroleum gas. 

200 DEFINITIONS 

201 BOILER: Any external combustion equipment fired with any fuel used to produce hot water 

or steam, excluding waste heat recovery boilers. 

202 BTU: British thermal unit or units. 

203 HEAT INPUT: The heat of combustion released by fuels burned in a unit based on the 

higher heating value of the fuel. This does not include the enthalpy of incoming combustion 

air. 

204 HEAT OUTPUT: The product Ho as defined in Section 9.3 of the South Coast AQMD 

Protocol, as referenced in Section 501 of this rule. 

205 LIQUEFIED PETROLEUM GAS: A compressed gas composed of one or more of the 

following flammable hydrocarbons: propane, n-butane, isobutane, propylene, and butenes. 

206 MOBILE HOME WATER HEATER: A water heater manufactured exclusively for mobile 

home use. 

207 NATURAL GAS: A mixture of gaseous hydrocarbons containing at least 80 percent methane 

by volume as determined according to American Standard Test Method (ASTM) D1945-64. 

208 POOL/SPA HEATER: A device in which water is heated when pool or spa water circulates 

through a heat exchanger. 

209 PROCESS HEATER: Any unit fired with any fuel which transfers heat from combustion 

gases to water or process streams. Process heater does not include any dryer in which the 

material being dried is in direct contact with the products of combustion, cement or lime kilns, 

glass melting furnaces or smelters. 

210 RATED HEAT INPUT CAPACITY: The heat input capacity specified on the nameplate of 

 the combustion unit. If the combustion unit has been altered or modified such that its 

maximum heat input is different than the heat input capacity specified on the nameplate, the 

new maximum heat input shall be considered as the rated heat input capacity. 

211 RECREATIONAL VEHICLE: A motor home, travel trailer, truck camper, or camping trailer, 

with or without motive power, designed for human habitation for recreational, emergency, or 
SACRAMENTO METROPOLITAN AQMD RULES AND REGULATIONS 

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other occupancy, as defined pursuant to Section 18010 of the California Health and Safety 

Code. 

212 WASTE HEAT RECOVERY BOILER: A device that recovers normally unused energy and 

converts it to usable heat. Devices incorporating duct or supplemental burners that are 

designed to supply 50% or more of the total rated heat input capacity of the device are not 

considered waste heat recovery boilers, but are considered boilers. Waste heat recovery 

boilers are also referred to as heat recovery steam generators. 

213 WATER HEATER: A closed vessel in which water is heated and is withdrawn for use 

external to the vessel at pressures not exceeding 160 psig, including the apparatus by which 

heat is generated and all controls and devices necessary to prevent water temperatures from 

exceeding 210 °F (99 °C). 

300 STANDARDS

301 EMISSION LIMITS: A person shall only distribute, offer for sale, sell, or install within the 

Sacramento Metropolitan Air Quality Management District a water heater, boiler or process 

heater with certified NOx and CO emissions less than or equal to the following limits: 

NOx Limit 

Nanograms per Joule of Heat Output 

(ppmv @ 3% O2)* 

CO Limit 

ppmv @ 3% O2

Heat Input 

Range 

and 

Type Effective 

3/1/1997 

Effective 

1/1/2011 

Effective 

1/1/2013 

Effective 

1/1/2011 

< 75,000 Btu/hr

Mobile Home 

All others 

50 

40 

40 (55) 

10 (15) 

No Limit 

No Limit 

75,000 to < 400,000 Btu/hr

Pool/Spa 

All others 

No Limit 

No Limit 

40 (55) 

40 (55) 14 (20) 

No Limit 

No Limit 

400,000 to < 1million Btu/hr

All Types No Limit 14 (20) 

 

400 

 * Where limits are shown in units of both nanograms per joule of heat output and ppmv at 

3% oxygen, compliance can be demonstrated using either limit. 

302 SELL-THROUGH OF WATER HEATERS, BOILERS AND PROCESS HEATERS: An 

applicable water heater, boiler or process heater manufactured prior to the January 1, 2011 

or the January 1, 2013 effective date specified for that unit in Section 301 may be distributed, 

offered for sale, or sold for up to 6 months after the specified effective date. In addition, a 

water heater, boiler or process heater manufactured before the effective date specified for 

that unit in Section 301 may be installed at any time, after the specified effective date, so long 

as it complied with the standards in Section 301 and 302 in effect at the time the unit was 

sold to the owner/operator of the water heater, boiler or process heater.

400 ADMINISTRATIVE REQUIREMENTS

401 CERTIFICATION REPORT: 

401.1 A manufacturer of any water heater, boiler, or process heater subject to Section 300 

shall submit to the Air Pollution Control Officer (APCO) a compliance report that 

demonstrates each model manufactured by it and subject to this rule is in 

compliance with the provisions of Section 300 at least 30 days prior to being sold or 

distributed for sale within the District. Regardless of whether a permit is required, the 

manufacturer submitting a certification report must pay the fee in Rule 301, PERMIT 

FEES – STATIONARY SOURCE, Section 311. The compliance report shall include 

the following information: 

a. Name and address of manufacturer; 
SACRAMENTO METROPOLITAN AQMD RULES AND REGULATIONS 

March 25, 2010 414-5 

b. Brand name and model; 

c. Model number as it appears on the rating plate; 

d. Fuel type unit is fired with; 

e. Description of each water heater model being certified; 

f. Heat input rating; 

g. All compliance test procedures and results, as performed by an independent 

testing laboratory, in accordance with Section 501; 

h. All calculations for determining compliance; and 

i. A signed and dated statement attesting to the accuracy of all statements 

and information in the compliance report. 

401.2 In lieu of Sections 401.1(g) and 401.1(h), a manufacturer may submit to the District, 

at least 30 days prior to a model being sold or distributed for sale within the District, 

an approved South Coast Air Quality Management District (SCAQMD) certification 

pursuant to SCAQMD Rules 1121 or 1146.2. 

402 MANUFACTURERS' LABELING REQUIREMENT: A manufacturer shall display the model 

number and the manufactured year of the water heater, boiler or process heater complying 

with Section 300 on the shipping carton and on the rating plate of each unit. The 

manufacturer shall also display the certification status on the shipping carton and on the 

water heater, boiler or process heater. 

500 MONITORING AND RECORDKEEPING

501 TESTING PROCEDURE: 

501.1 Any natural gas-fired water heater, boiler or process heater to which this rule applies 

shall be tested in accordance with the South Coast Air Quality Management District 

Protocol: Nitrogen Oxides Emissions Compliance Testing for Natural Gas-Fired 

Water Heaters and Small Boilers, as amended January 1998. 

501.2 Any water heater, boiler or process heater fired with a fuel other than natural gas, to 

which this rule applies, shall be tested in accordance with the test methods below. 

All emission determinations shall be made while the unit is operating according to the 

manufacturer’s recommendations. Tests shall be conducted while the unit is 

operating at a firing rate that is as close as physically possible to the unit’s 

recommended heat input capacity. Tests shall consist of three 40-minute sampling 

periods. Results shall be averaged over the three test periods. Test reports shall 

include the operational characteristics of all flue-gas NOx reduction equipment. 

a. Oxides of Nitrogen – ARB Method 100 or EPA Method 7E. 

b. Carbon Monoxide – ARB Method 100 or EPA Method 10. 

c. Stack Gas Oxygen – ARB Method 100 or EPA Method 3A. 

d. Carbon Dioxide – ARB Method 100 or EPA Method 3A. 

502 DURATION OF RECORDS: A manufacturer shall keep test reports and certification records 

for as long as the water heater, boiler or process heater model is offered for sale or sold in 

the District, or for three calendar years after manufacture, whichever is longer. These 

records shall be made available to the Air Pollution Control Officer upon request.
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