One sprinkler hour a week, priced on your bill

A sprinkler water bill on WSSC Water rates grows fast: one hour a week for 13 weeks adds about $433.67 to a 145-gallon-a-day house’s 90-day bill, by our arithmetic.

By the Your Water Numbers desk, not WSSC Water · Updated November 2, 2026 · How we check

Reading this: Every row assumes the whole watering season lands in one 90-day bill. The next section prices the split.

Why does a single hour cost so much?

Volume plus tier. WSSC Water’s conservation page puts a standard sprinkler at about 1,300 gallons for one hour a week, and that water lands on top of your indoor use, in the highest rate tier you reach.

One sprinkler hour costs $23.27 at the Tier 1 rate, $31.50 at Tier 3 and $39.68 at Tier 4 (our arithmetic). Once a summer bill has reached Tier 4, each hour you skip saves that $39.68.

Does it matter how the season falls across bills?

Yes, and splitting helps. Tiers go by average daily use in the bill period, so the same water spread over two bills pays less.

One hour a week split evenly across two 90-day bills adds $393.57, against $433.67 on one bill. Two hours a week add $867.34, against $949.46 (our arithmetic). You don’t pick your bill dates, but this explains why two neighbors running the same schedule can see different totals.

How much does household use change by season?

We can’t give you a curve. No official monthly household series turned up, so this page works from sprinkler arithmetic instead of a seasonal chart we can’t source.

The best series you have is your own. Lay your last four bills out, divide gallons by days and compare same-season pairs on the gallons-a-day table.

How do you price your own sprinkler?

Measure it. The 1,300 figure is a standard estimate, not your yard. With nothing else running, read the meter before and after an hour.

Then take gallons per hour, multiply by your hours and your weeks, divide by the bill’s days and add your indoor average. Read that row in the table. A College Park lawn and a Gaithersburg lawn pay the same tiers, so only the gallons differ.

When should you stop watering altogether?

When asked. On Sept. 29–30, 2026 all customers were asked for essential use only, including no outdoor water, to avoid a boil-water advisory. The notices page explains the types.

Connecting a sprinkler system properly

An irrigation connection needs a licensed plumber, and a permit where required. Plumbing work in these counties requires a WSSC Water license: how to check one.

Questions on this page

Where each number comes from