Plain-English explainers, every claim cited

How California watering rules work

The schedule pages give the watering days your supplier sets. These guides explain the rules behind the numbers: the state ordinance every landscape plan is checked against, the climate figure that sets the watering, and what an HOA can and cannot ask for. Each guide cites the adopted state text, the statute or our verified datasets, section by section.

Start with your question

I am planning a new yard or a remodel

The city checks the landscape plan against a water budget. These four guides walk the budget in order.

My HOA wrote to me about the lawn

What the state lets an association demand during a drought, what it cannot, and the one exception.

HOA and brown lawns

I want the numbers behind my watering

Where the climate figure comes from and why drip earns credit that sprinklers do not.

All six guides

Water budgetsThe Two Numbers That Decide Your Landscape Water BudgetEstimated water use vs the budget cap: what feeds each number, why plants and drip matter most, and what happens when a plan runs over.4 min read · 4 primary sources · 5 parts The climate numberWhat Is ETo? California Reference EvapotranspirationWhat reference evapotranspiration (ETo) measures, why it runs from the high 30s on the coast to the 90s in the desert, and how watering scales from it.3 min read · 2 primary sources · 4 parts Small projectsThe Prescriptive Path for Small California LandscapesSmall California landscape projects can skip the water budget math and follow the section 492 checklist instead. Every requirement, in plain language.4 min read · 1 primary source · 6 parts HOA rulesCan Your HOA Fine You for a Brown Lawn in California?Civil Code 4735 blocks HOA fines for cutting back lawn watering during a declared drought emergency. What is void, what still applies, and one exception.4 min read · 2 primary sources · 5 parts Irrigation mathDrip vs Sprinklers in a California Water BudgetWhy California's landscape water budget credits drip at 0.81 efficiency vs 0.75 for spray, and how that 7 percent gap helps a yard pass its budget.4 min read · 2 primary sources · 4 parts Edible areasEdible Gardens in a California Water BudgetVegetable gardens and orchards count at a full 1.0 in a California landscape water budget instead of 0.55. What qualifies and how to claim it.4 min read · 2 primary sources · 4 parts

Put the rules to work

CalculatorWater budgetThe two numbers for your own plan, with the adopted factors.WorksheetSubmission worksheetThe filled worksheet a city asks for with a landscape plan.SchedulesYour water daysThe days and hours your supplier sets, city by city.

Guides checked against the adopted text on August 27, 2026. Every page carries its own sources and the date each was read.