Enter your lawn size and water rate — see what each watering week costs, the season total, and what dormancy would save.
The water bill math
gallons = sq ft × inches × 0.623
cost = gallons ÷ 1,000 × your rate
The 0.623 is just unit conversion (one inch of water on one square foot is 0.623 gallons), and it makes the invisible visible: "an inch a week" sounds free until it's 3,000 gallons with a price on it. This is also the number that makes every water-saving habit quantifiable instead of virtuous.
A worked example
5,000 sq ft, $6 per 1,000 gallons, 1 inch across 16 dry weeks: 3,115 gallons and $19 a week — about $299 a season. A rainy summer that covers 4 of those weeks hands back $75 for checking a rain gauge. Dormancy through the 8 hottest weeks (sipping a half inch every 2–3 weeks instead) keeps roughly $130 of it.
Cheaper inches, same lawn
The watering calculator turns these inches into sprinkler minutes (and counts rain), the mow-tall setting measurably cuts evaporation, and deep-rooted grass from deep-and-infrequent watering simply needs fewer inches to look the same. The expensive lawn habits and the unhealthy ones turn out to be the same list.
Frequently asked questions
How much does it cost to water a lawn?
An inch of water over 1,000 sq ft is 623 gallons — so a 5,000 sq ft lawn drinking its weekly inch uses about 3,100 gallons, which at a typical $6 per 1,000 gallons runs ~$19/week, $300+ per season. Your numbers above give your exact bill.
Why is my summer water bill so high?
The lawn is almost always the answer: outdoor watering commonly doubles or triples a household's summer usage. Many utilities also price in tiers — the lawn's gallons land in the most expensive tier — and some add sewer charges to irrigation water that never reaches a drain (ask about a separate irrigation meter or sewer credit).
How can I lower my lawn watering bill?
In order of payoff: count rain honestly (skip watering after a wet week), water early morning (20–30% less evaporation loss), mow taller (shade cuts soil evaporation), fix sprinkler overspray onto pavement, and let the lawn go golden-dormant in peak summer if your grass type handles it — dormancy is a survival feature, not death.
Is letting the lawn go dormant in summer okay?
For cool-season lawns, usually yes: they brown out, sip about a half inch every 2–3 weeks to keep crowns alive, and green back with fall rain. The trade: 6–8 weeks of golden lawn and some thinning in a brutal year. Many households save $150–300 a summer this way.