Water and wells in SLO County: what buyers should check, town by town

Cambria is the strictest water regime in the county. The Cambria Community Services District declared a water-shortage emergency under Water Code Section 350 in November 2001, and it has never been lifted. The district isn’t issuing any new residential or commercial water or wastewater connections. No new residential Intent-to-Serve letters have gone out since 2001.

The wait list isn’t a queue that moves. It closed to new applications on December 31, 1990. More than 600 parcels sit on it, and the district’s single-family list alone runs to 656 positions as of March 2026. The list hasn’t moved since the moratorium began. A position can be transferred to an eligible parcel and carries a small annual administration fee. But holding one isn’t a water connection. The county’s adopted growth rate for Cambria is zero.

A vacant Cambria lot without a water position is effectively unbuildable until the moratorium changes, however attractive the price. A parcel with existing service is a different conversation entirely. That’s why the same street can hold a functioning home and a lot that has waited three decades.

The long-term supply question runs through the district’s Water Reclamation Facility. It would make the 2014 emergency supply system permanent. The project cleared the county in 2026. The Planning Commission unanimously approved its Coastal Development Permit on February 26, and the Board of Supervisors denied all six appeals on June 16. Six appeals were then filed with the California Coastal Commission under a single appeal number, A-3-SLO-26-0017. On September 9, 2026, the Commission voted unanimously that the appeals raised no substantial issue. So the county decision stands and is final and effective, and the Commission’s own appeal route is exhausted. Opponents who want to press further would have to go to court. The ruling has two limits. It doesn’t authorize new service connections or lift the moratorium. And it didn’t finish the plant’s permitting. The district still needs approvals from the regional water board, Fish and Wildlife and the Army Corps, or confirmation that none are required.

Los Osos was under a building moratorium from the late 1980s until 2024. The Coastal Commission approved the Los Osos Community Plan with modifications on June 13, 2024. The county accepted those modifications on October 29, 2024, and the plan was certified on December 11, 2024. What replaced the moratorium is real but narrow. On December 16, 2025, the county Board of Supervisors set the 2026 residential allocation at 25 new dwelling units, a 0.4% growth rate. Of those units, 75% are reserved for parcels inside the sewer service area. Allocations went first to the county’s Waitlist to Build, in order. From October 1, 2026, any unused 2026 allocations open to every parcel in the sewer service area on a first-come, first-served basis. The county expects 15 to 20 to be left.

An allocation isn’t enough on its own. A new home also needs habitat-mitigation credits under the Los Osos Habitat Conservation Plan, and for 2026 those have run out. The county released its first pool of roughly 55,000 credits on May 1, 2026. By September 17, 2026, every one had been reserved. The county is accepting no more credit applications this year and expects new credits in early 2027. When credits are available, the reservation is short-lived. The building permit application and its initial fees are due within 45 days of the county issuing a Credit Reservation Form, or the credits go back to the pool.

On August 13, 2026, the California Fish and Game Commission also voted to list Morro manzanita as threatened under the California Endangered Species Act. If a biologist’s survey finds Morro manzanita on a lot, the project must avoid and minimize harm to it. It must also meet the California Department of Fish and Wildlife’s own requirements, on top of the habitat plan.

The groundwater basin underneath is adjudicated. Three purveyors and the county manage it under a 2015 stipulated judgment, and it carries a state critical-overdraft designation. How much growth it can carry is disputed on the record. Coastal Commission staff wrote in January 2026 that the best available science shows the basin isn’t in overdraft and has enough water for new development. The Basin Management Committee recommended zero growth for 2026 instead, citing a new groundwater model and deteriorating basin conditions. The three water purveyors urged the county to follow that recommendation. The Board of Supervisors chose its groundwater director’s 0.4%. If you’re buying in Los Osos, both positions are part of the record you should know.

One more check is specific to Los Osos. The community sewer began operating in 2016, and the parcels it serves carry two county charges on the property tax bill. One is an annual sewer service charge. The other is an assessment repaying the loans that built the system. The assessments run to 2048 and 2053. If you’re buying, ask for the parcel’s sewer charges in escrow.

The Templeton Community Services District (TCSD) gates new water connections with a policy that requires at least a 20% supply buffer. It releases new “water units” only when its buffer model shows supply to spare. For years that meant almost no releases, and a single unit was released after the February 18, 2025 review. Then the picture changed. In June 2025, the board revised the policy to credit future treated-wastewater flows and released 249 units. That left only three properties on the wait list by the end of 2025. The board released 58 more after the February 17, 2026 review. As of February 2026, unassigned units go first come, first served to owners who submit a will-serve application.

If you plan a new build, a second unit or any intensification of use on a TCSD parcel, confirm water-unit availability with the district first. Units are far easier to come by than before mid-2025. But they still go through the district’s will-serve process, and the pool shrinks as units are claimed.

The state has designated the Paso Robles groundwater subbasin as critically overdrafted. The Department of Water Resources approved its Groundwater Sustainability Plan, and the plan’s five-year evaluation was submitted in January 2025. In August 2025, landowners rejected a proposed funding fee from the Paso Robles Area Groundwater Authority. That’s no longer the end of the story. In May 2026, the authority adopted a groundwater sustainability fee under a different part of the Water Code. It’s charged per acre-foot of consumptive use and collected on the county property tax roll.

If the home is on City of Paso Robles water, you’re largely insulated. In a normal year, more than half the city’s water comes from shallow wells along the Salinas River, supplemented by Nacimiento Lake water and basin groundwater. The diligence load lands on rural and acreage parcels served by private wells over the subbasin. There, the well itself is part of what you’re buying.