Water Usage Calculator

Estimate daily and monthly household water use by activity, with an optional monthly usage-charge estimate.

Estimated Result

—

Enter your values and calculate.

Clear breakdowns

Review inputs and totals

Transparent formulas

Understand the estimate

Works on any device

Mobile, tablet or desktop

How to Use the Water Usage Calculator

Enter household-wide daily frequencies, not a per-person frequency. For showers and faucets, set gallons per minute, minutes per use and uses per day. For toilets and appliances, set gallons per flush or cycle and events per day. Fractional frequencies such as 0.5 cycles per day represent an average. Enable the custom activity for another flow or per-use estimate. Choose the month length and optionally enter dollars per 1,000 US gallons.

Formula and Explanation

Flow: gallons/day = gal/min × minutes/use × uses/day
Event: gallons/day = gal/event × events/day
Monthly gallons = daily total × days
Monthly usage charge = monthly gallons ÷ 1,000 × rate

For flow activities, daily gallons = gallons per minute × minutes per use × uses per day. For flushes or cycles, daily gallons = gallons per event × events per day. Add all activities, then multiply by the selected 28–31 days. Monthly usage charge = monthly gallons ÷ 1,000 × dollars per 1,000 gallons.

Actual water rates vary. This estimate may exclude sewer charges, fixed fees and tiered pricing. It assumes the same daily pattern across the month. Irrigation, leaks and other unlisted use are excluded unless you add them through the custom activity. Use fixture labels, meter readings and your actual bill when available.

Worked Example

Two 8-minute showers per day at 2 gallons per minute use 32 gallons per day. Over 30 days that is 960 gallons. At $5 per 1,000 gallons, the shower-only usage charge is $4.80. The on-page defaults are editable example assumptions rather than measured household averages.

Frequently Asked Questions

Are the frequencies per person or per household?

Enter totals for everyone in the household. If two people each shower once a day, enter two shower uses per day. Do not multiply those totals by household size again.

Can I enter laundry that happens only a few times a week?

Yes. Divide weekly cycles by seven for an average daily frequency. For example, 3.5 cycles per week is 0.5 cycles per day. The monthly estimate assumes that average remains constant.

Where can I find my water price?

Use your bill or water provider’s published usage rate, expressed in dollars per 1,000 US gallons. A bill may also contain sewer charges, minimums, fixed fees or tiers that this single-rate estimate does not include.

Does the calculator include outdoor use or leaks?

Only the listed activities are counted. Enable the optional custom activity to estimate another flow-based or per-use activity. Unmeasured leaks and any other omitted activities are not automatically included.