High bill — but no leak?

Confirm the leak screen really passed

Overnight no-use + toilets. “I don’t hear dripping” is not a test.

• Meter check: EPA WaterSense suggests reading the meter before and after a two-hour period when no water is being used. If the meter changes at all, you probably have a leak.
• Toilet dye test: put a few drops of food coloring in the tank. EPA says that if any color shows up in the bowl after 10 minutes, you have a leak.

Silent leaks are common enough to rule out properly. EPA says an old or worn flapper can silently leak thousands of gallons a year, and that nine percent of homes have leaks that waste 50 gallons or more per day.

Compare units and rates MoM

Flat use + higher $ → rate/fee/sewer story. Higher use + clean indoor tests → outdoor or occupancy.

• Divide billed usage by the number of days in each billing period, so a longer period does not look like a spike.
• Convert units if needed. EPA notes that one CCF (hundred cubic feet) equals 748 gallons.
• Compare with the same billing period last year, not just last month. EPA notes that water use and bills are often higher in summer, and that a rise in use you cannot explain by more outdoor watering could be a sign of a leak.
• Check whether the current or previous read was estimated. See estimated meter read true-up.

Have both bills in hand? The two-bill spike splitter splits the difference into billing days, usage per day, rate or tier, sewer and fees.

Check for a rate, tier, or surcharge change

Your bill can rise even when your usage does not. EPA describes rate structures that do this, including increasing block (tiered) rates, seasonal rates that charge more in summer, and drought rates that rise with the local drought level. Many bills also combine a fixed charge with a per-unit charge.

Real example, as checked October 3, 2026: Denver Water added temporary drought charges starting with May 2026 water use (June 2026 bills): $1.10 per 1,000 gallons on Tier 2 and $2.20 per 1,000 gallons on Tier 3. Tier 1 is exempt. For an Inside City of Denver single-family customer with an average winter consumption of 7,000 gallons who uses 25,000 gallons in a month:

1. Tier 1 (first 7,000 gallons): 7 × $3.02 = $21.14.
2. Tier 2 (next 15,000 gallons): 15 × $6.54 = $98.10, of which 15 × $1.10 = $16.50 is drought charge.
3. Tier 3 (remaining 3,000 gallons): 3 × $9.45 = $28.35, of which 3 × $2.20 = $6.60 is drought charge.
4. Volume charges: $21.14 + $98.10 + $28.35 = $147.59. Of that, $16.50 + $6.60 = $23.10 is drought charge, a charge that did not apply to the same usage before May 2026.

Rates are Denver Water's 2026 Inside City single-family rates per 1,000 gallons including drought charges, before the monthly fixed charge. Your utility's rates and tiers will differ; read the rate table on your own bill.

Winter averaging can follow you into later bills

Some utilities use your winter water use to set charges for the rest of the year. A winter leak, extra guests, or unusually low winter use can change later bills even when the leak screen is clean now. See winter sewer averaging.

• Seattle Public Utilities: single-family sewer bills are based on actual water use from November through April. From May through October, if you use more water than in winter, the sewer bill is based on your average winter use; if you use less, it is based on actual summer use.
• Denver Water: Tier 1 is based on average winter consumption, the average of billed use on bills dated January, February, and March, recalculated each year. The Tier 1 allotment is 5,000 to 15,000 gallons per month, so a low winter average means summer use reaches the higher-priced tiers sooner.

Interrogate irrigation timing

According to EPA WaterSense, outdoor water use is more than 30 percent of total household use on average and can be as much as 60 percent in arid regions. EPA also says replacing a clock-based controller with a WaterSense labeled irrigation controller can cut an average home's irrigation water use by up to 30 percent, saving up to 15,000 gallons a year.