ADU Builder in Three Springs, Westlake Village

Which City Permits a Three Springs ADU?

Three Springs Drive and the core of the neighborhood are inside the City of Westlake Village, and the area has its own zone in the City's landscaping district. But the name travels. Some nearby homes marketed as Three Springs are actually across the line in the City of Thousand Oaks, in Ventura County. The two cities have different ADU ordinances, different submittal steps and different building departments.

A wrong assumption here costs months. Plans drawn for Westlake Village's Zoning Clearance and Los Angeles County plan check will not match what Thousand Oaks expects, and the reverse is also true. We check the assessor's parcel record and the city boundary for your address before we sketch anything, and we tell you which set of rules applies on the first call.

Three Springs Lots Near the Foothills and ADU Fire Rules

Being south of the lake puts Three Springs closer to the open hillsides that rise toward the Santa Monica Mountains. Some lots back onto slopes or natural open space. That affects an ADU in two ways. First, the flat portion of the yard may be smaller than the parcel map suggests, so placement and foundation type need early attention. Second, parcels near open land are more likely to fall in a mapped fire hazard severity zone.

The 2018 Woolsey Fire affected Westlake Village, and the City has begun preparing a Community Wildfire Protection Plan. Where your parcel is mapped in a hazard zone, the ADU has to be built to wildland-urban interface standards: Class A roofing, ember-resistant vents, ignition-resistant exterior materials and tempered glass in specified locations. Defensible space around the new unit also has to be planned with the landscaping.

• Check the parcel's fire hazard severity zone map
• Class A roof and ember-resistant vents
• Ignition-resistant siding, decks and eaves
• Defensible space planned with the ADU footprint

ADU Types That Suit Three Springs Homes

On the flatter interior streets, a garage conversion or a junior ADU is usually the simplest start. Inside City limits, Los Angeles County's pre-approved standard plans for those two conversions are available, and the City links to them. They can trim design time when the space fits.

Where the backyard slopes, an attached ADU built beside the house often beats a detached unit. It sits on the existing building pad and keeps utility runs short. On lots with a usable flat yard, state law permits a detached cottage of no more than 800 square feet, placed as close as four feet to the side and rear lines.

If the parcel turns out to be in Thousand Oaks, the same unit types are available, but the design is built around Thousand Oaks standards, including its oak tree protections.

Three Springs ADU Permits Step by Step

For a Three Springs home inside the City of Westlake Village, City planners compare the design with the ADU rules in Municipal Code 9.14.070, and a compliant project receives a Zoning Clearance. The building permit is then issued by the County's Building and Safety division on the City's behalf, using the EPIC-LA system. For a home on the Thousand Oaks side, that city's Community Development Department reviews both planning and building.

Either way, review is ministerial, with no public hearing, and the agency must meet the state's 15 business day completeness check and 60 day decision deadline for a complete application on a lot with an existing home.