Is My Water Bill High? What to Look For & How to Tell

Multifamily water benchmarks by gallons per day and by monthly cost, plus how to tell when your usage signals a problem.

Most property owners and managers can quote their occupancy rate, their payroll per unit, and their rents against the comps down the street. Ask what their water use per unit should be, and the honest answer is usually a shrug.

That’s not negligence. There’s simply nothing to compare it to. The bill arrives, it gets paid, and unless it doubles overnight, “high” and “normal” look identical. Municipal billing makes it harder, since rate structures vary from city to city and billing errors are more common than most operators realize.

You don’t know what you don’t know. And what you don’t know could be costing thousands in wasted water and draining your property’s value.

So here is the short answer: healthy multifamily communities typically operate between 90 and 110 gallons per occupied unit per day. On the cost side, most properties pay between $40 and $80 per occupied unit per month for water and sewer, with high-cost utility markets running $80 to $150 or more. Once a property climbs past 125 gallons per unit per day, there’s usually something worth investigating.

The two ways to measure water “per unit”

When people ask about average water use per apartment unit, they usually mean one of two different metrics:

• Average monthly water and sewer cost per unit. The budgeting number. Useful for forecasting and expense comps.
• Average consumption per unit, in gallons per day (GPD). The operational number. Useful for spotting waste.

Both matter, but they answer different questions. Cost tells you what you’re paying. Consumption tells you whether you should be paying it.

How many gallons per day should an apartment unit use?

Industry benchmarks for multifamily consumption:

Note that the denominator is occupied units. Vacant units barely use water, so measuring against total units makes a wasteful property look efficient on paper.

What does water and sewer cost per apartment unit per month?

Cost also varies meaningfully by property class:

Here’s the catch: two properties with identical consumption can have very different bills depending on local utility rates. A property in a high-rate city can run efficiently and still pay more than a wasteful property in a cheap market. That’s why we benchmark in gallons, not dollars. GPD travels across markets. Cost doesn’t.

Getting to that accurate GPD number usually requires looking under the hood. A water audit is the best tool for the job. It’s an easy way to establish an accurate benchmark you can fully trust.

Why do older properties use more water?

The Class C premium isn’t only about rates. Older communities tend to carry:

• Aging toilets that use far more water per flush than modern fixtures
• Worn flush valves that let water run unnoticed
• Underground leaks between the meter and the buildings
• Higher occupancy density
• Older plumbing infrastructure throughout

Each of these quietly raises both consumption and maintenance costs. None of them announces itself on the bill.

How do I know if my property is using too much water?

Calculate your number first: total gallons billed, divided by days in the billing period, divided by occupied units. Then place it on this scale:

One caution from our audit work: improvement and “fixed” are not the same thing. One property we worked with brought consumption down from 187 GPD per occupied unit to 157 after initial repairs. Real progress, but still well above an optimal target of roughly 114 GPD, which meant meaningful savings were still on the table.

What does excess water use actually cost?

A useful rule of thumb: every 10 GPD above benchmark can represent thousands of dollars in unnecessary annual water and sewer expense, depending on the property’s size and local utility rates.

The gallons add up faster than most people expect. For a 200-unit property:

• 10 GPD of excess = roughly 730,000 gallons of excess water per year
• 50 GPD of excess = roughly 3.65 million gallons per year

Waste at that scale isn’t a rounding error. It’s a recurring operating expense hiding inside a utility line item. When it’s found and fixed, the savings flow straight into net operating income, and that improvement compounds into what the property is ultimately worth.

How do you lower water use per unit?

Once a property lands in the “needs investigation” zone or above, the fixes usually come from a familiar set of sources:

• Leak detection. Underground and slab leaks can run for months without ever surfacing.
• Fixture repairs and retrofits. Running toilets and worn flush valves are the most common culprits we find.
• Usage monitoring. Continuous-flow alerts catch problems in days instead of billing cycles.
• A water bill audit. High “usage” isn’t always real. Billing errors, misapplied multipliers, and estimated reads can quietly inflate your costs while the meter tells a completely different story. Even if your bill seems normal, a water audit is the best way to uncover hidden mistakes and establish your true benchmark.

Know your number

The whole point of a benchmark is that you stop guessing. Ten minutes with a recent bill and a rent roll will tell you whether your property is running lean, running average, or quietly paying for water nobody is using.

A high number is only the starting point. At Argen, we help you understand what’s behind it and take the steps to bring it down, from leak detection to fixture repairs to ongoing monitoring.

Frequently Asked Questions