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Photograph of huge water tanks at an old property with a well having a slow recovery rate. Home Water Quantity Requirements

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How to estimate daily water quantity usage & wastewater quantity:

This article outlines typical daily residential water usage in gallons for people, appliances, and activities. s.



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Home and Outdoor Living Water Requirements, Plumbing Fixture and Appliance Water Flow Rates

Collapsing building © Daniel FriedmanKnowing the average and peak water usage rates for people, fixtures, or buildings permits estimation of wastewater volume (for septic tank size determination) as well as water and well flow requirements and assists in water pump capacity or sizing specifications.

Flow rates for common household plumbing fixtures and appliances is given as well as estimates of peak demand water usage rates for residential buildings.

This data is also useful when evaluating adequacy of private well and water supply quantity, well flow rate, and wastewater loads on onsite residential septic systems.

Daily wastewater volume to be treated and disposed-of at a site determines the design parameters for onsite wastewater treatment or septic systems as well as suggesting choices among alternative septic designs and septic product

How much water does a family use each day? What is the water flow rate for common household fixtures and appliances? How is this data used? Here we will review the following

The following table lists water usage requirements and typical fixture flow rates or device flow rates for home and outdoor living in the U.S.

Table 1. Home and Outdoor Living Water Requirements
Typical Plumbing Fixture Water Usage & Flow Rates

Use Flow Rate
US Gallons
GPM
Flow Rate
Liters
LPM
Total Use
U.S. Gals.
Total Use
Liters
Adult or child total water use - - 60 - 70 / day1
50 - 100 / day2
227 - 2651
189 - 3792
Baby care - - 100 / day 379
Bathroom % of Residential Water Use   50 - 75%1
 
Bathroom lavatory sink 2 7.6 1 - 2 / use 3.8 - 7.6
Backwash filters 10 37.9 100-200 / backwash cycle 379 - 757
Dishwasher 2 7.6 5 - 5 / load 19 - 57 / load
Garbage Disposer 3 11.3 4 - 6 / day 15 - 23 / day
Kitchen sink (a) 3 11.3 2 - 4 / use 7.6 - 15 / use
REVERSE OSMOSIS
water treatment
*   3 - 10 wastewater / gal.
of treated water produced
11.3 - 37.8 / gal
Shower or tub 5 19 25 - 60 / use 95 - 227 / use
Shower head, standard 4 - 7 15 - 26.5    
Shower head, low-flow 2 or less      
Toilet flush - standard pre 1980 toilets 3 11.3 4 - 7 / use 15 - 26.5 / use
Toilet flush - vintage 1980-1992 3.5 / use 13 / use
Toilet flush - low-water-consumption 1.6 / use or less 5.7 / use
Toilet flush - high-efficiency HET 1.28 / use 4.84 / use
Outside hose faucet 5 19 depends on run time  
Water softener regeneration 5 19 50 / 100/cycle 189 / 379
Washing machine, clothes,
standard domestic
5 19

29-55 / load2, 3
13+ / cu.ft. capacity

109 - 208 / load

Washing machine, clothes,
water-efficient
15-30 / load2, 3
9.5 / cu. ft. capacity
57 - 114 / load
Washing machine, clothes,
high efficiency

5 / cu.ft. capacity

19 / cu.ft. capacity
19 / 0.28 m3

Notes to Table:

(a) water flow restricting valves and shower heads can reduce flow and water use by up to 50%.

Sources:

  1. RESIDENTIAL WATER USE TABLE [PDF], New York City Department of Environmental Protection, retrieved 2017/09/15, original source: http://www.nyc.gov/html/dep/html/residents/wateruse.shtml
  2. USDA "Water Systems Handbook." (Thanks to Keith Oberg, Professional Home Inspection Service, Binghamton, NY, for providing this information.)
  3. Clothes Washer Water Use, Home Water Works, Alliance for Water Efficiency, ret. 2017/09/16, original source http://www.home-water-works.org/indoor-use/clothes-washer

This data is used to estimate daily wastewater use in order to apply the septic tank sizing table located at SEPTIC TANK SIZE

*Reverse Osmosis Systems - impact on septic systems and water use

What about water volume from reverse osmosis water treatment systems? These can vary by manufacturer with a range of 3:1 to 10:1 of waste to product efficiency. "Typically" for every gallon produced with a topo of the line system, 3 to 5 gallons goes into the septic tank. Less efficient systems (regardless of shutoffs) can dump up to 10 gallons to waste for every gallon that goes into the storage tank.

See REVERSE OSMOSIS CONCENTRATE WASTE DISPOSAL for further details. -- Larry Newcomb Encinitas Learning Center. We also discuss the effects of increased water usage when buildings use reverse osmosis (RO) for water purification.

Also see HOT WATER QUANTITY DAILY USE - daily hot water usage rates & tables

 

Table of Peak Water Demand Usage Rates Translates into GPM Requirements for Water Pumps

Typical Residential Building Water Usage Rates: Flow Rates & Plumbing Fixtures
Water Usage PointWater Flow
GPM1
Peak
Demand2
Water Volume
Gals
Total Water Flow Rate GPM for Number of Bathrooms in Use at Once3
1 1 1/2 2 - 2 1/2 3 - 4 Comments
Bath Sink Lav
4
2
2
4
6
8
 
Dishwasher
2
14
   
3
3
 
Kitchen Sink
5
3
3
3
3
3
 
Shower
5
35
35
35
53
70
 
Toilet
4
5
5
10
15
20
 
Tub
5
35
35
35
53
70
 
Washing Machine
(Clothes)
5
35
 
18
18
18
WASHING MACHINES & SEPTIC SYSTEMS
Peak Demand
Total Gallons2
 
45  
70  
98  
122  
SEPTIC TANK SIZE
Minimum Water Pump
GPM Capacity Needed
 
7
10
14
17
WATER PUMP CAPACITIES TYPES RATES GPM
Gallons Per Hour Flow Rate
 
420
600
840
1020
 

Notes:

1. These are WSC's average fixture flow rates for common household plumbing fixtures. In some cases new fixtures are provided with low-flow-rate orifices or heads that can substantially reduce these flows. For example shower heads may restrict flow to about 2 gpm as may lavatory faucets.

2. Average household total gallons of water used during a theoretical peak demand period of seven minutes. I.e. all fixtures are in use overlapping in time for this interval. This is the peak demand water volume used just during that interval. In my OPINION these numbers may not represent typical household usage.

For example someone washing dishes by hand at a kitchen sink usually runs water for longer than 3/5 of a minute (3 gallons taken at a 5 GPM rate means that the kitchen faucet was open for just about 36 seconds or that water was run more slowly so as to consume 3 gallons over a 7 minute interval).

3. Notice that there is a presumed reduction in flow rate when multiple bathrooms are in use simultaneously. For this reason the individual or single fixture flow rates are not simply added together. The table also assumes that either a shower or tub is in use in a given bathroom but not two such fixtures in the same bath for the same interval.

Adapted from: Water Systems Council (2003)

Also see HOT WATER PEAK DEMAND USE

...


Continue reading at SEPTIC SYSTEM DESIGN: INTRO or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see WATER HEATER SIZE SPECIFICATION - daily hot water usage rates & tables

Or see PLUMBING DRAIN FIXTURE UNITS DFUs - measure of the wastewater volume or loading of a drain waste or vent system

Or see SEPTIC SYSTEM DESIGN ALTERNATIVES - home

Or see SEPTIC SYSTEM DESIGN BASICS - home

Or see SEPTIC SYSTEM DESIGN REGULATIONS

Or see SEWAGE FLOW & DESIGN FLOW ESTIMATES - plumbing fixture flow rates

Or see WATER CONSERVATION MEASURES

Or see these

Water & Wastewater Quantity Articles

Septic System Design Codes & Regulations Articles

Suggested citation for this web page

WATER QUANTITY USAGE TABLES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS

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