Calabasas: water, sewer and permits
Calabasas is the newest city in Los Angeles County: it incorporated on April 5, 1991, the 88th of the 88. It covers about 13.3 square miles along U.S. 101, with Agoura Hills to the west, Hidden Hills to the north, Los Angeles at Woodland Hills to the east, and unincorporated county land, including Malibu Creek and Topanga State Parks, to the south. Its neighborhoods are commonly listed as Old Town Calabasas, home of the Leonis Adobe, usually dated to 1844; Park Moderne; Calabasas Park around Calabasas Lake, a man-made lake said to date from the late 1960s; Calabasas Highlands; Mountain View Estates; and Mont Calabasas, reported to have joined the city in 2011.
The Census puts about 9,400 housing units in Calabasas, with a median year built of 1984. Only 38 percent went up before 1980, the 1980s are the largest decade at 34 percent, and 60 percent of homes are detached single-family houses, with condos, townhomes and apartments making up most of the rest. Houses of that era were typically plumbed with copper, and copper that has carried hard water for around forty years is where pinhole leaks, stiff shutoff valves and failing heater connections begin to turn up.
The Las Virgenes Municipal Water District, based on Las Virgenes Road in Calabasas, supplies the water, all of it imported State Water Project water, disinfected with chloramines. In 2025 its hardness averaged 142 mg/L, or 8.3 grains per gallon, ranging from 119 to 176 mg/L. That counts as hard water: it builds scale at the bottom of tank heaters, inside tankless heat exchangers and on aerators and valve seats. A backflow assembly on an irrigation or fire sprinkler line needs a certified tester to check it every year at the least.
Public sewer mains are maintained by the County Sewer Maintenance District, and LVMWD treats the wastewater at the Tapia plant on Malibu Canyon Road. The owner is responsible for the whole lateral, including the part under the street. Plumbing permits come from the City's own Building and Safety Division at 100 Civic Center Way; its applications are described as online only, and a water heater replacement is listed among the jobs that need a permit. The 2025 California Plumbing Code took effect statewide on January 1, 2026, and the City is reported to have adopted it. SoCalGas supplies the gas.
Calabasas borders Los Angeles, Hidden Hills and Agoura Hills. We take calls from each of them on the same 24-hour line. The plumber follows a leak or a blockage back to its source before cutting into any wall or floor, and nothing proceeds until you have signed a written estimate.
Neighborhoods we come to
- Old Town Calabasas
- Park Moderne
- Calabasas Park
- Calabasas Highlands
- Mountain View Estates
- Mont Calabasas
ZIP codes in Calabasas we cover
- 91302
- 91301
- 90290





