Drive onto Westlake Island and you are in Ventura County. Drive off and you are in Los Angeles County. A 2011 Acorn history of the Conejo Valley's borders explains why. The 1960s developer had to give each county access from its own side, so instead of building two bridges, he built one bridge on the county line.
The same line runs under your water meter. On the Los Angeles County side, each home's water allowance is set by how many people live there and how much of the lot gets irrigated. On the Ventura County side, every home in the Cal Water Westlake District pays on the same fixed tiers, whether it's a townhome or an estate. For buyers looking at large, heavily landscaped lots, that difference shows up every month and never appears on a listing sheet.
Most of "Westlake Village" is in Thousand Oaks
The original master-planned community of Westlake Village was "transected diagonally by the Los Angeles and Ventura county line," as city officials put it to The Acorn in January 2024. The Los Angeles County side covers 3,456 acres. It incorporated as the City of Westlake Village in 1981. The Ventura County side covers the other 8,544 acres of what used to be Russell Ranch, including the western half of Westlake Lake. Thousand Oaks annexed it in two pieces, in 1968 and 1972.
That means roughly seven of every ten acres in the original master plan sit outside the city that carries the name. Both cities share the 91361 and 91362 ZIP codes. In the same 2011 Acorn piece, Scott Wolfe, then planning director for the City of Westlake Village, said that people in North Ranch often assume they live in the City of Westlake Village when they actually live in Thousand Oaks.
The name is a mailing convention. The water utility is decided by jurisdiction, and the two main systems on either side of the line set prices in very different ways.
The city side: a water budget written for each household
The City of Westlake Village is one of the communities served by Las Virgenes Municipal Water District. LVMWD bills against a budget specific to each customer. According to the district's water budget page, three inputs set that budget:
- Resident count. Each resident adds about 1.9 HCF, roughly 1,400 gallons, to the monthly indoor budget.
- Irrigated area. The outdoor budget follows the amount of regularly watered landscaping. LVMWD estimates it from aerial imagery and property information, and swimming pools count toward it.
- Weather. The outdoor allowance rises in long, hot months and shrinks in short, cool ones.
Water used within the budget is billed at the efficient rate, and use above it moves into the higher tiers. For 2026, LVMWD's residential commodity rates are $4.56 per HCF for Tier 1 Efficient, $7.68 for Tier 2 Inefficient, and $9.05 for Tier 3 Excessive. Those rates include a $0.92 pass-through charge from the Metropolitan Water District of Southern California. A standard ¾-inch household meter also carries a $58.79 monthly readiness-to-serve charge.
What matters for a large lot is that the efficient tier is not a fixed number of units. A household of five on an acre with a pool gets a larger efficient allowance than a couple in a townhome, because the budget is designed to grow with occupants and irrigated area.
The Ventura side: the same tiers for every home
Across the line, Cal Water's Westlake District serves part of Thousand Oaks. The district was formed in 1983 when Cal Water bought the Westlake Water Company. Its residential tariff, effective January 1, 2026, covers "Westlake Village, in the southern part of Ventura County, within the City of Thousand Oaks and vicinity." It uses four volume tiers that are the same for every single-family customer.
| LVMWD, City of Westlake Village | Cal Water Westlake District, Thousand Oaks | |
|---|---|---|
| How tiers are set | A budget for each customer based on residents, irrigated area and weather | Fixed volume brackets, the same for every home |
| Lowest rate | $4.56 per HCF within budget | $1.8254 per CCF for units 1 to 6 |
| Middle rates | $7.68 per HCF above budget | $7.2951 for units 7 to 25; $9.1182 for units 26 to 44 |
| Top rate | $9.05 per HCF | $13.6761 per CCF above 44 units |
| Monthly fixed charge | $58.79 for a ¾-inch meter | $36.68 for a ⅝ x ¾-inch meter; $55.02 for a ¾-inch meter |
| Rates dated | 2026 schedule | Effective January 1, 2026 |
HCF and CCF are the same unit: 100 cubic feet, or about 748 gallons.
The Cal Water schedule is cheap at the bottom and steep at the top. The first six units cost about $1.83 each. Any unit above 44 costs about $13.68, roughly seven and a half times as much. Those brackets stay the same no matter how many people live in the house or how much lawn surrounds it. Under the January 2026 tariff, a home using 30 CCF in a month would pay about $195 in quantity charges before the service charge. That figure comes from simple arithmetic across the first three tiers. It is an illustration, not a bill estimate.
The two systems split right at the large-lot buyer. On the LVMWD side, a big irrigated parcel comes with a bigger efficient allowance. On the Cal Water side, the same parcel uses more water against the same brackets as everyone else, so summer irrigation moves it into the top tier sooner. Which side costs less for a given home depends on household size, lot size and how much of the yard is watered.
The Cal Water tariff above took effect January 1, 2026, and included a 4.99% revenue increase, which the tariff attributes to higher costs for wholesale water, recycled water and purchased power. Cal Water files tariff revisions with the California Public Utilities Commission, so check its Westlake District page for the current schedule before using these figures for a specific home.
The friction that shows up after closing
On the LVMWD side, the budget is tied to facts about the household that change when a home changes hands. The district asks customers to keep their resident count current. It also notes that sanitation charges go up with additional residents, so a larger household gets more indoor water allowance and also pays more for sewer service.
Irrigated area is estimated from aerial imagery. A buyer who removes turf, adds a pool or replants a hillside is living with a budget built on the old layout until someone files an update. LVMWD's water budget adjustment request handles permanent changes to resident count or landscape area. It also covers medical need, livestock and licensed care facilities. A landscape change requires a drawing or sketch showing landscape square footage and pool or spa surface area, leaving out the house and hardscape. Adjustments are subject to district review and take effect on the date the request is received, not the date the change was made.
LVMWD asks for a residential start-service application at least one business day before service begins. The district's published pages don't say whether a seller's budget settings carry over to a new account or reset, so ask the district directly during escrow.
There is also a quieter step that comes first. The City of Thousand Oaks lists several water purveyors inside its boundaries and links to a provider map. Triunfo Water & Sanitation District provides services in the Westlake Village and North Ranch portions of Thousand Oaks. A Ventura-side address does not automatically mean Cal Water, so confirm the provider by address.
Why the gap widens in a dry year
Both systems rely on imported water. All of LVMWD's drinking water is purchased from MWD and comes from Sierra Nevada snowmelt delivered through the California Aqueduct. The district keeps a reserve in Las Virgenes Reservoir and treats water at the Westlake Filtration Plant or at MWD's Jensen plant. Cal Water's Westlake District buys imported surface water from MWD through Calleguas Municipal Water District.
That shared dependence on the State Water Project made 2022 especially hard. The Acorn reported in August 2022 that outdoor water budgets in western Los Angeles and eastern Ventura counties were cut to 50% on June 1. It also reported that LVMWD's allotment from MWD had been cut by 73%. In the same article, LVMWD executive Joe McDermott told the Calabasas Chamber of Commerce, "Our service area is ground zero for the drought." The Los Angeles Times reported that LVMWD's enforcement started with door-tag warnings, escalated through penalties, and could end with flow restrictors after three offenses of using more than 150% of budget.
A budget system can tighten every household's allowance at once, which is what the 50% cut did. On a fixed-tier system, a shortage shows up as watering rules and the steep top tier.
Today's rules reflect where each system stands. Cal Water says its customers are currently in Stage 1 of its Water Shortage Contingency Plan and that watering restrictions vary by city. LVMWD's current rules ban irrigation from 10 a.m. to 5 p.m., during rain, and within 48 hours after measurable rain. They also prohibit runoff and allow flow restrictors or termination of service after repeated violations.
What changes on the city side through 2030
LVMWD's new rates took effect January 1, 2026, under a five-year plan approved through Proposition 218 in 2025. The board reaffirms each year's adjustment. According to the district, customers who use water efficiently will see an average increase of about $13 more per month each year through 2030. Part of that money goes to the Pure Water Project, which LVMWD expects to begin operating in 2028. The project will eventually supply up to 30% of the community's drinking water from recycled water, which reduces reliance on imported supply.
For a buyer weighing two homes a mile apart, that timeline belongs in the same column as HOA dues and the property tax rate.
Quick answers
Is Westlake Lake in the City of Westlake Village? Only part of it. The western half sits in Ventura County, in the City of Thousand Oaks.
Does the documentary transfer tax differ across the line? In the sources reviewed, both sides work out to about 0.11% of the sale price, so this is not where the two sides differ. California City Finance's transfer tax table, effective December 1, 2025, lists both Westlake Village and Thousand Oaks at $0.55 city plus $0.55 county per $1,000.
Can an LVMWD customer change the budget after a remodel? Yes. Submit a budget adjustment request with a sketch of landscape and pool areas. Changes take effect from the date the district receives it.
If you are comparing homes on both sides of the county line, Nico Torres can help you confirm which water provider serves each address, compare the rate structures, and decide which questions to ask the utility before your contingencies expire. Work with Nico.
This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.
