Why is my water bill so high?

Winter outdoor hose timer before you dispute

A forgotten hose timer can add outdoor gallons while the house feels quiet. Size it with the hose timer outdoor water check before you fight the utility.

After heavy rain, check Drainage Delay first

Retained runoff can delay stormwater charges for a day or two. Size retained vs billed gallons with the how runoff retention changes your stormwater bill toy before you dispute the utility.

Name the four causes before you spend money

When people ask why is my water bill so high, they usually mean the total dollars jumped. Dollars can jump for four different reasons:

1. More water used — guests, irrigation, pool fill, new laundry habits, or a longer billing period.
2. Higher price per unit — rate changes, seasonal surcharges, or an increasing-block (tiered) rate that put you into a more expensive block.
3. Sewer / wastewater rules — sewer often tracks water volume, uses a winter average, or applies a cap. The same gallons can cost far more on the sewer line than on water.
4. Silent waste — toilet flappers, irrigation valves, and service-line leaks that run without an obvious drip sound.

EPA WaterSense notes that household leaks waste about 180 gallons per week on average, easy fixes can save about 10% on the water bill, and about 9% of homes have leaks wasting 50 gallons or more per day. Those numbers are large enough to move a monthly bill — but only if the cause is actually a leak.

The job of this guide is not “use less water forever.” It is to identify which of the four causes applies this cycle, then run one test that would prove it.

Compare usage units, not just dollars

Open this bill and the previous one (or the same month last year). Write down three numbers for each cycle:

• Total $ (what you paid)
• Usage units (CCF, HCF, 1,000-gallon units, or gallons — whatever the bill prints)
• Number of days in the billing period

Then compute gallons (or units) per day. A longer cycle can look like a “high bill” even when daily use is normal. A flat unit total with a higher $ total points to rates, fees, or sewer — not your shower length.

If the bill only shows dollars, check the utility portal for usage graphs. Many portals show daily or hourly use that the paper statement hides.

Run the quiet-house leak screen (two hours of no use)

This is the single highest-leverage step when the bill spiked and you do not already know the cause:

1. Turn off every fixture (including ice makers and irrigation controllers if you can).
2. Read the meter (or photograph the dial / digital display).
3. Wait at least two hours with nobody using water, or do an overnight no-use window. EPA WaterSense uses a two-hour no-use check: if the meter changes at all, you probably have a leak.
4. Read again. If the meter moved with the house quiet, you have continuous flow — leak territory, not “be slightly better in the kitchen.”

Then dye-test every toilet: food coloring in the tank, wait 10 minutes without flushing. Color in the bowl without a flush means a flapper or flush-valve path is leaking. EPA WaterSense says a worn flapper can silently leak thousands of gallons a year, enough to erase careful dishwashing savings for weeks.

Hearing a faucet drip (not a silent toilet)? Size drips → gallons → $/month with the Drip Meter before you shrug it off.

If the service valve at the house can be closed and the meter stops, the leak is on the house side. If the meter still moves with the house valve closed, call the utility — the problem may be on the service line.

Ask whether sewer is the multiplier

In many U.S. cities, the sewer line item is larger than the water line item even when both track volume. Common patterns:

• Volumetric sewer — every wasted gallon is billed twice (water + sewer).
• Winter averaging — summer irrigation may not fully hit sewer, but a quiet winter toilet leak can set a high sewer average for months.
• Caps / irrigation exemptions — outdoor use may be partially excluded from sewer; indoor leaks never are.

Real 2026 numbers (Seattle Public Utilities): inside Seattle, off-peak water is $5.82 per CCF while sewer is $20.18 per CCF (1 CCF = 748 gallons). For single-family homes, SPU bases sewer on water use from November through April, and summer sewer bills use that winter average. So a leak that runs all winter costs about $26 per CCF while it runs, and it keeps inflating sewer on summer bills after you fix it. (SPU sewer rates, SPU water rates)

If usage units are flat but the total rose, read the sewer rate language on the utility site before replacing fixtures. If usage rose and sewer is volumetric, fixing the usage cause pays on both lines.

Check tiers, fees, and the billing calendar

Increasing-block rates charge more per unit after you cross a threshold. Being one unit over a tier can matter more than shaving a few shower minutes.

• Find the tier table on the bill or rate PDF.
• Note fixed fees, drought surcharges, stormwater, or “readiness to serve” charges that do not move with habits.
• Confirm the service period dates — estimated reads that later true-up can create a sudden high bill without a lifestyle change. See estimated meter read true-up.

Real 2026 numbers (Denver Water, inside Denver): Tier 1 runs from 0 up to your average winter consumption (AWC, your average January to March use, floored at 5,000 and capped at 15,000 gallons) at $3.02 per 1,000 gallons. Tier 2 covers the next 15,000 gallons at $5.44, and Tier 3 is everything above that at $7.25. Under Stage 1 drought pricing (May 2026 use through April 30, 2027), Denver adds $1.10 to Tier 2 and $2.20 to Tier 3, so summer gallons above your winter baseline cost $6.54 to $9.45 per 1,000, which is two to three times the Tier 1 price. (Denver Water 2026 rates)

If you are near the next tier, the highest-value experiment is often staying under that threshold for the rest of the cycle — not buying a new dishwasher.

Worked example: the same spike on two real 2026 rate schedules

Two households, two real rate schedules, two different reasons the bill jumped. Both use published 2026 residential rates; your utility's numbers will differ, but the method is the same.

Denver: a stuck irrigation zone crosses two tiers. Assume an average winter consumption of 6,000 gallons, so Tier 1 is 0 to 6,000, Tier 2 is 6,001 to 21,000, and Tier 3 is above 21,000. The fixed charge for a standard 3/4-inch meter is $20.91.

• Normal summer month, 14,000 gallons: 6 × $3.02 = $18.12, plus 8 × $6.54 = $52.32, plus $20.91 = $91.35 for water.
• Zone stuck on, 26,000 gallons: 6 × $3.02 = $18.12, plus 15 × $6.54 = $98.10, plus 5 × $9.45 = $47.25, plus $20.91 = $184.38 for water.

Use went up 86% but the water bill went up 102%, because the extra 12,000 gallons were billed at Tier 2 and Tier 3 prices ($93.03, or about $7.75 per 1,000 gallons). Denver Water bills water only, so any sewer charge is on top.

Seattle: a silent winter toilet leak where sewer does the damage. A flapper leaking 50 gallons a day (EPA says about 9% of homes have leaks at least that large) adds 3,000 gallons, or about 4.0 CCF, to a 60-day winter bill.

• Water: 4.0 CCF × $5.82 = $23.34
• Sewer: 4.0 CCF × $20.18 = $80.94

That is $104.28 per bill, and 78% of it is sewer. Because SPU uses winter water use to set summer sewer for single-family homes, the same leak can keep costing you after the flapper is replaced. That is why the leak screen comes before any rate argument.

Rates checked September 2026 from Denver Water and Seattle Public Utilities. Rates change; confirm yours on your utility's rate page.

If the leak screen is clean, interrogate outdoor and occupancy

Outdoor watering averages over 30% of household water use nationally and, according to EPA WaterSense, can be as much as 60% in arid regions. Classic non-leak spike drivers:

• Irrigation controller still on a peak-summer schedule after cooler weather or rain
• Broken heads misting sidewalks, or a zone stuck on
• Pool fill / spa top-off
• Guests, a home renovation, or a new washer that is not high-efficiency
• A water softener regenerating more often than you expect — size the gallons with the softener regeneration cost calculator

Walk the system while it runs once. Compare the controller’s days/minutes to roughly 1 inch of water per week including rainfall for many cool-season lawns (plant needs vary — the point is “default clocks overwater”).

Only then rank indoor fixtures — and prove one change

Indoor use is dominated by toilets, showers, faucets, clothes washers, and leaks — not mystery kitchen habits. After you know the cause class:

1. Fix continuous flow first (leaks).
2. Change one outdoor schedule parameter if the spike is seasonal.
3. Then consider WaterSense fixtures with a calculator, not a shopping spree.

The cleanest proof is a one-unit savings sprint: remove one billing unit this cycle and know which branch caused the drop. Or upload the PDF for a ranked plan.