Quick answer: A typical apartment uses about 50–80 gallons per unit per day, or roughly 1,600–2,400 gallons a month, when nothing is leaking. In NOWi's study of 102 leak-free San Francisco buildings (mostly one-bedroom units), the average was 53.2 gallons per unit per day, about 1,600 gallons a month (NOWi Multifamily Water Usage Benchmark Study). Usage rises with more residents, older fixtures, hot climates, and leaks. A unit consistently above 80 gallons per day very likely has a leak.
Average Apartment Water Use: The Numbers
| Measure | Typical value | Source |
|---|---|---|
| Per apartment unit, per day (no leaks) | 53.2 gal (range 33–82; 96% of buildings between 45–75) | NOWi SF study |
| Per unit, per day, citywide multifamily (incl. irrigation, common areas) | 117 (Tampa Bay) to 182 (Phoenix) gal | Water Research Foundation |
| Per person, per day, indoors in apartments | 33.3 gal (efficient fixtures) to 55.7 gal (older fixtures) | University of Arizona Water Wise |
| Per person, per day, multifamily (Seattle region) | 40 gal | Saving Water Partnership |
| Per person, per day, indoors (Scottsdale multifamily) | 58 gal (89 gal per unit at 1.5 people) | Scottsdale Water |
| Average U.S. family at home (houses and apartments) | 300+ gal per day, ~70% indoors | EPA WaterSense |
Apartments use less water per unit than single-family homes, mainly because households are smaller and there is little or no private landscaping (WRF).
Monthly Water Use by Household Size
Bedrooms matter less than the number of people living there. The City of Madison, WI publishes these monthly ranges for its residents (houses and apartments combined):
| People in the home | Gallons per month |
|---|---|
| 1 | 1,800–2,900 |
| 2 | 2,900–5,000 |
| 3 | 5,000–7,000 |
| 4 | 7,500–10,000 |
Source: City of Madison Water Utility. Apartments with efficient fixtures and no in-unit laundry usually land at the low end.
What Drives Apartment Water Use
- Number of residents: the biggest factor by far.
- Toilets: the largest indoor use, about 27% of household water. Pre-1994 toilets use 3.5–7 gallons per flush, versus 1.28 or less for WaterSense models (EPA).
- Showers and faucets: a bathroom faucet runs about 2 gallons per minute (EPA). See how many gallons a shower uses.
- Laundry: older washers can use 50+ gallons a load; efficient models use under 27 (EPA).
- Leaks: the one driver that adds cost with no benefit to anyone.
Leaks: The Hidden Share of Your Water Bill
A leaky toilet can waste about 200 gallons a day, and the average household's leaks waste more than 9,300 gallons a year (EPA WaterSense). In a building, those losses add up across every unit and are rarely reported by residents.
NOWi's monitoring data shows how common this is:
- In the San Francisco benchmark study, 21% of buildings had leaks, and those buildings averaged 99.7 gallons per unit per day, nearly double leak-free buildings. Leaks made up 12% of all water used (study).
- In a Los Angeles portfolio of 47 buildings, 72% were leaking in the first week of monitoring (read the case study).
- At one garden-style property, a single leak ran at 1,521 gallons per hour, about $24,092.64 a month (case study).
How to Calculate Your Building's Water Use Per Unit
- Take total gallons from a recent bill (1 CCF = 748 gallons). Use a winter bill if irrigation isn't on a separate meter.
- Divide by the number of occupied units.
- Divide by the days in the billing period.
Compare the result to the benchmark: above 80 gallons per unit per day (or above 70 for buildings with more than 10 units), a leak is highly likely (NOWi benchmark). Learn how to read a water meter to check overnight usage.
How NOWi Helps Apartment Owners Catch Leaks Early
The NOWi Meter Monitor attaches to your existing water meter and tracks the whole building's usage, flagging continuous flow and overnight usage that signal a leak. The Pipe Monitor clamps onto a pipe to watch a specific line, such as a riser or irrigation feed.
Owners catch leaks before they show up on a bill or turn into water damage. In San Francisco, 11 of 24 monitored buildings had leaks, and the system paid for itself in under 2 months. Devices run on cellular, so there's no Wi-Fi to set up.
See how NOWi works for apartment buildings →
Frequently Asked Questions
How much water does a 1-bedroom apartment use per month?
Usually about 1,500–2,500 gallons for one or two people with no leaks. NOWi's leak-free one-bedroom-heavy buildings averaged about 1,600 gallons per unit per month.
How much water does one person use per day in an apartment?
About 33–58 gallons indoors, depending on fixtures and climate (UA Water Wise, Scottsdale Water).
Is 3,000 gallons a month a lot for an apartment?
For one person, yes. It's above Madison's typical range for a single-person home and could point to a leak. For two or three people it's within normal ranges.
How do I know if my apartment building has a leak?
Calculate gallons per unit per day. Consistently above 70–80, or water use that never drops to zero overnight, points to a leak. A meter monitor shows this in real time. If you manage a building, see our multifamily leak detection buyer's guide for how to compare monitoring options.
Related: What is the ROI of a water monitoring system? · What is NOI?
1 comment
I have a rental one story with 4 efficiencies and one bed apartment. I am looking to install water meters if it’s physically possible. Please let me know if you sell anything that would be suitable?
Thank you.