Citywide
City of Los Angeles
Water saved by building denser
Yards
An average single-family lot has about 2,450 sq ft of irrigated yard, which uses about 57,000 gallons a year today. Townhomes and apartments that replace a house keep little irrigated landscape.
Total demand: who uses the water
Every water figure is total use: households, plus businesses and government, plus 8% for leaks and unbilled water. Only the Total Demand section at the bottom of the Area tab breaks it into parts.
- Rates per resident. Today's rates come from Los Angeles Department of Water and Power (LADWP) billing divided by Census population: about 89 gallons a day for people in single-family houses and 59 for people in apartments. The single-family rate is adjusted by each area's climate (reference evapotranspiration, or ETo, a measure of how much water plants lose to heat and sun), so the Valley's yards need about 4% more water than the citywide average and the Harbor's about 15% less.
- 2075 rates are today's rates times 0.803, the conservation factor: savings keep growing until they reach about the technical maximum in LADWP's 2017 conservation study.
- New homes. New apartments use the apartment rate, cut about 9.5% for tenants who pay for their own metered water. Townhomes built under SB 1123 and SB 684 (state laws allowing up to 10 small homes on a lot) and ADUs (accessory dwelling units: backyard homes and garage conversions) use less, because they come with little or no irrigated yard. Houses that add an ADU or an SB 9 home lose the irrigated part of the yard under it (SB 9 is a state law allowing a second home on a single-family lot). On a lot with a house, the first ADU takes yard; of second ADUs, half are junior ADUs built inside the house and half are second detached ADUs (allowed by AB 956, a 2026 state law), so half take yard. ADUs on 2–4 unit lots take yard; those on larger apartment lots don't.
- Yard percentages. Each is a share of today's lots of that type. For ADUs and SB 9 homes, the line counts single-family lots that add at least one, as a share of today's single-family lots. A lot can hold more than one ADU, and each SB 9 lot gets two homes, so there are more homes than lots. The model counts SB 9 lots and ADU lots separately. Irrigated yard area removed is a share of today's irrigated yard on single-family and 2–4 unit lots, at about 2,450 sq ft per lot (the state Department of Water Resources' 2023 measurement for LADWP's service area). It counts whole yards on rebuilt lots plus half of each footprint of ADUs and SB 9 homes that take yard.
- Yards replaced counts single-family lots rebuilt as townhomes or apartments, plus 2–4 unit lots rebuilt as apartments. Partial yard losses under ADUs and SB 9 homes count in the irrigated area and watering figures, not in the count.
- Water saved by building denser compares the projection with every resident using water at the rate of their area's housing mix today (after the same conservation). Business use and leaks are the same in both. Citywide, that comparison gives 987,000 AFY in total, against 840,000 in the projection.
- Total demand adds commercial, industrial and government use (held at its 2030 rate per resident) and 8% for leaks and other unbilled water, which brings the city to about 840,000 AFY in 2075. The model has no job locations, so for each area, business use is spread in proportion to residents. That understates it in job centers such as Downtown and Century City and overstates it elsewhere.