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Chapter 3 – Current M&I Demands 

3.1 Introduction 

This chapter presents current M&I water use information for the study area (including water for 

parks, golf courses, etc.). Agricultural water use is discussed in Chapter 4 as a part of the section 

on Projected Future Supplies. The data collected for the most recent update of the M&I Water 

Supplies Study (M&I Study) for the Weber River Basin has been used as a basis for this report. 

Some of the information considered includes data from related investigations recently completed 

by UDWR and the Utah Division of Water Rights. 

3.2 Data Collection and Methodology 

Each year, UDWR targets particular hydrologic basins or study areas for M&I water supply and 

use analysis. The Division of Water Right’s water use data form sent to UDWR by the 

community water systems of the state is the primary tool for these analyses. 

UDWR contacts the manager and/or operator(s) of each public community water system (as 

defined by UDDW) to schedule a data analysis meeting. During such meetings, UDWR attempts 

to retrieve any missing data as well as obtain an overall feeling of the supplies and demands of 

the water system, in case estimates are necessary. All of the community water systems for the 

various basins studied have cooperated and provided the necessary M&I water supply and use 

data. 

An important part of the data collection process is to determine the present water use for each 

community water system. Present water use, as defined herein, includes the developed water 

that is actually diverted into the distribution system from surface or subsurface sources. 

The most recent M&I study for the Weber River Basin was started in May 2002 by UDWR. 

Data from the 2001 Municipal and Industrial Water Use Forms, distributed by the Division of 

Water Rights in cooperation with UDWR and UDDW, were used as a basis for the study. The 

data for the Snyderville Basin that is shown in this chapter was presented to local water providers 

in the fall of 2004 to identify significant discrepancies and ensure its accuracy. 

3.3 M&I Water Use Classifications 

M&I water use is divided into four categories: residential, commercial, institutional, and 

industrial. The residential category includes water used in residential homes for inside and 

outside uses. The commercial category includes water use for retail establishments and 

businesses. The institutional category includes water use for Government facilities, military 

facilities, schools, hospitals, churches, parks, cemeteries, golf courses, etc. The industrial 

category includes industrial and mining with a wide variety of water uses associated with 

businesses that produce a specific product. 
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3.3.1 Residential Use 

This use is associated with residential cooking, drinking water, clothes washing, personal 

grooming and sanitation, irrigation of lawns, gardens and landscapes, and miscellaneous inside 

and outside cleaning. Single family homes, apartments, duplexes, and condominiums are some 

examples of buildings with residential water use. 

UDWR collects data from the system operator about the number of residential connections and 

the amount of water used by those connections. Water use in this category is divided into three 

subcategories: culinary-outside, culinary-inside, and secondary-outside use. The first step in 

calculating the amount of water used in each of these subcategories is determining the amount of 

indoor water use. When individual water meter readings are available, indoor water use can be 

estimated by looking at several individual homes' winter meter readings, totaling the water use, 

and dividing it by the number of households and/or residents. If this method yields an 

unreasonable value, then UDWR will use information from their December 2000 report of 

Identifying Residential Water Use. The report contains a graph that indicates the relationship of 

persons per household and the appropriate indoor water use in gallons per capita per day 

(GPCD). The person per household data is obtained from the Utah State Governor's Office of 

Planning and Budget. This data is retrieved for each county and used with the above-mentioned 

graph to obtain a GPCD value. This value is then multiplied by the community water system's 

customer population to yield the water system's total indoor water use. 

Once indoor water use has been determined for the year, it is then subtracted from the total year's 

residential water use given by the system's operator. The result represents the amount of water 

used during the summer months for outdoor applications. This amount is then checked with the 

value calculated by using the average lot size within the water system's service area, percentage 

that is irrigated, the irrigation efficiency, and the consumptive water use for the type of 

landscaping in the area. 

3.3.2 Commercial Use 

Commercial water uses are normally associated with small business operations that may include 

drinking water, food preparation, personal sanitation, facility cleaning and maintenance, and 

irrigation of facility landscapes. Retail businesses, restaurants, and hotels are some examples 

where commercial water use occurs. 

For most systems, the system operator can separate metered commercial water use data from the 

total water use. In cases where this data is not available or is extremely difficult to obtain, 

UDWR attempts to estimate commercial water use by inventorying commercial businesses in the 

area and using published commercial water use estimates. These publications come from the 

UDDW and from reports published by the Utah State Water Laboratory. In some rural 

communities where there are a relatively small number of commercial connections, the 

businesses are individually visited by UDWR and asked about their water use. 

3.3.3 Institutional Use 

Institutional water uses are normally associated with the general operation of various public 

agencies and institutions. Examples include water used for city, county, state and Federal 

Government facilities, parks, golf courses, schools, hospitals, churches, military facilities, fire 
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hydrant testing, and other municipal losses in the water system. Because this water use is rarely 

metered in total, the process to acquire this data is difficult. Again, the system operator is asked 

to provide information about city facilities such as number and size of parks, schools, churches, 

and golf courses. Water right duty rates for the area are used to calculate the amount of water 

these areas use. Also, the estimates made of leakage and testing of water system facilities is 

included in this category. 

3.3.4 Industrial Use 

Industrial water use is associated with the manufacturing or production of products. The volume 

of water used by industrial businesses can be considerably greater than water used by 

commercial businesses. Manufacturing plants, oil and gas producers, mining companies, and 

dairies are some examples where industrial water use occurs. Industrial water use within 

community water systems is acquired with the same process used to obtain commercial water use 

data discussed earlier. 

3.3.5 Private-Domestic Use 

Private domestic use includes water from private wells or springs for use in individual homes, 

usually in rural areas not accessible to public water supply systems. Due to the lack of records 

associated with this type of water use, quantities are usually estimated. Generally, a population 

assumed to be served by private wells is determined by taking the difference between the total 

population of a county or other jurisdiction and the number of people served by the public 

community water system(s) within the jurisdictional boundaries. Calculated gallons per capita 

water use rates for the area are then used to determine a total use for this category. A record of 

the number of active private well water rights is another method of determining private domestic 

water use. Each active water right is assumed to be a "typical" family, using approximately 

1 acre-foot of water annually. 

3.4 M&I Water Use Data 

By definition, municipal and industrial (M&I) water use is a combination of all residential, 

commercial, institutional, and industrial uses. It includes the total water (potable and 

non potable) supplied by public water systems (community and non community), self-supplied 

industries, private domestic systems, and secondary irrigation companies. 

Within the study area are the following public community water systems: Community Water 

System, Gorgoza Mutual Water Company, High Valley Water Company, Mountain Regional 

Special Service District, Park City Water, Summit County Service Area No. 3, Summit Water 

Distribution Company, and Timberline Special Improvement District. Also included in the study 

area are the self-supplied industries Duke Energy Field Services and United Park City Mines 

Company, along with the Summit County Public Works facility. 

3.4.1 Current Use Estimates 

Table 3-4 summarizes the 2001 total M&I water use for the study area which is further broken 

down by system and category of use in Tables 3-1 through 3-3 as explained below. 
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Table 3-1 shows a breakdown of the potable water use for each public community system for the 

base data year of 2001. This table shows that for the study area, the total current annual potable 

water use is 8,182 acre-feet. Given a service population of 23,065 people, the per capita daily 

potable water use of public community water systems in the study area is 317 gpcd. 

Secondary water is another important aspect of total M&I water use. Table 3-2 shows the 

amount of secondary water use for public community systems. In the study area, secondary 

water is supplied for some residential uses, but mostly for commercial and institutional purposes, 

for a total use of 1,225 acre-feet. 

Table 3-3 gives the estimated water use for public non-community systems and private domestic 

systems. Summit County Public Works is one of the three non-community systems within the 

study area. There are two self-supplied industries in the study area. Combined, these uses 

amount to 153 acre-feet of potable water and 274 acre-feet of non-potable water for the year 

2001. 

Total potable M&I water use in the study area for 2001 is 8,335 acre-feet, while non-potable 

water use is 1,499 acre-feet, giving a total M&I water use of 9,834 acre-feet. 

TABLE 3-1 

2001 Potable Water Use for Public Community Water Systems

POTABLE USAGE (Acre-Feet/Year) 

Summit County Water 

Supplier 

Residential 

Indoor 

Residential 

Outdoor 

Commercial 

Total 

Institutional 

Total 

Industrial 

Total 

TOTAL 

M&I 

Service 

Population

Gallons 

Per 

Capita 

Per Day 

Community Water Co. 77 44 42 0 0 163 200 727

Gorgoza Mutual Water Co. 305 239 0 40 0 583 3,340 156

High Valley Water Co. 30 45 0 0 0 75 450 149

Mountain Regional SSD 576 1,021 60 15 5 1,677 5,760 260

Park City Culinary Water 630 1,822 1,146 150 0 3,748 8,050 416

Summit Co Service #3 34 46 0 0 0 80 420 170

Summit Water Distribution 437 1,253 135 15 0 1,840 4,660 352

Timberline Special Imp. Dist. 13 3 0 0 0 16 185 78

STUDY AREA TOTALS 2,102 4,472 1,384 220 5 8,182 23,065 317
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TABLE 3-2 

2001 Secondary Water Use in Public Community Systems

Summit County Water 

Supplier 

Residential 

Use 

(Ac-Ft/Yr) 

Commercial 

Use 

 (Ac-Ft/Yr) 

Institutional 

Use 

 (Ac-Ft/Yr) 

Industrial/ 

Stockwater 

Use 

 (Ac-Ft/Yr) 

Total 

Secondary 

Use 

 (Ac-Ft/Yr) 

Community Water Company 0 0 0 0 0

Gorgoza Mutual Water Co. 0 0 0 0 0

High Valley Water Company 0 0 0 0 0

Mountain Regional SSD 20 0 0 0 20

Park City Culinary Water 100 650 230 0 980

Summit Co Service No.3 0 0 0 0 0

Summit Water Distribution 0 225 0 0 225

Timberline Special Service Dist. 0 0 0 0 0

STUDY AREA TOTALS 120 875 230 0 1,225

TABLE 3-3 

2001 Water Use for Public Non-Community Water Systems, 

Self-Supplied Industries and Private Domestic Systems 

POTABLE USAGE 

Residential 

Use 

(Ac-Ft/Yr) 

Commercial 

Use 

(Ac-Ft/Yr) 

Institutional 

Use 

(Ac-Ft/Yr) 

Industrial/ 

Stockwater 

Use 

(Ac-Ft/Yr) 

Total 

Potable 

Use 

(Ac-Ft/Yr) 

Total 

Secondary 

Water Use 

(Ac-Ft/Yr) 

County Facilities: 

Summit County Public Works 0 0 2 0 2 0 

Subtotals 0 0 2 0 2 0 

Self-Supplied Industries1 0 0 0 1 1 274 

Private Domestic Systems 150 0 0 0 150 0 

STUDY AREA TOTALS 150 0 2 1 153 274 

1

Duke Energy Field Services, United Park City Mines Co. 

Note: The estimated population served by private domestic systems is 500 persons. 

TABLE 3-4 

2001 M&I Water Use Summary

Uses 

Potable 

(Acre-Ft/Yr) 

Secondary 

(Acre-Ft/Yr) 

Total Use 

(Acre-Ft/Yr) 

Water Use for Public Community Water Systems 8,182 1,225 9,407

Water Use for Non-Community, Self-Supplied 

Industries and Private Domestic Systems 153 274 427

Total Water Use 8,335 1,499 9,834
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3.4.2 Comparison of Current Use with Available Water Supply 

Figure 3-1 compares the current M&I water use in the study area with the basin safe yield and 

available water supply identified in Chapter 2. The area under the lower hydrograph is labeled 

as Current Uses and depicts the demand pattern of Park City (MWH, May 2002) multiplied by 

2.3 to adjust it to the total water supply volume of 9,834 acre-feet (UDWR) delivered by all 

entities in the Basin during 2001. From this figure, it can be seen that the Available Supply 

exceeds the Current Uses during much of the year. However without significant storage, this 

excess supply cannot be used to meet the peak period requirements. The supply is limited by the 

connections it can serve during peak demand periods. The figure shows that the current uses 

nearly match the presently available supply from August through November. 

Downstream Storage 

FIGURE 3-1 

Snyderville Basin Current M&I Use vs. Available Supply and Basin Safe