Buying a Home in Los Gatos? What to Know About Septic Systems and Private Wells

Los Gatos is known for distinctive hillside homes, privacy, and natural surroundings. Some properties, especially in rural and hillside areas, rely on private wells or onsite septic systems rather than public water and sewer. These systems are not automatically problems, but buyers should investigate them before purchasing.

Why utility systems matter

Before buying, verify whether the property uses public sewer or an onsite wastewater treatment system, whether its water comes from a public utility or an individual or shared well, who maintains the systems, and what permits and inspection records exist. Never assume all hillside properties use the same utilities.

Understanding a septic system

A septic system treats wastewater onsite. Its condition depends on design, age, soil conditions, maintenance and usage. Request permits, prior inspection records, pumping history, repair documentation, and a map identifying the tank and dispersal area. Ask a qualified inspector to assess condition, capacity, access and potential issues.

Santa Clara County rural property sale requirements

Santa Clara County has point-of-sale requirements for certain rural real estate transactions involving onsite wastewater treatment systems. Buyers and sellers should confirm which requirements apply to the specific parcel, obtain appropriate evaluations and disclosures, and resolve inspection or repair questions before relevant contingencies are removed. Structures or paving over system components can complicate access.

What to know about private wells

Private wells require attention to both water quality and production capacity. A well may produce sufficient water but need treatment, or have acceptable water quality but inadequate yield. Request well permits, maintenance history, laboratory results, equipment records, and any shared-well agreements. Consult a qualified well professional for property-specific advice.

Water testing and disclosure

For covered rural real estate transfers beginning September 1, 2025, Santa Clara County requires individual water system testing for water quality and yield, with related seller disclosures. Verify the current requirements and review the actual test results. Valley Water also recommends routine testing of domestic well water for coliform bacteria, nitrate and electrical conductivity.

Planning a remodel or ADU

If you intend to add a bedroom, expand the house or build an accessory dwelling unit, confirm whether the existing septic system and water supply can support the project. Expansion may require new permits, system upgrades or a replacement dispersal area. Speak with the county environmental health department, planning and building officials, and appropriate licensed professionals before relying on expansion potential.

Could you connect to public sewer?

A future sewer connection may be possible but is not guaranteed. Feasibility depends on location, available infrastructure, district rules, connection fees and potential extensions. Ask the appropriate utility district for parcel-specific requirements and cost estimates.

Buyer due-diligence checklist

Confirm actual water and wastewater sources; obtain available permits, plans and inspection reports; inspect the septic system; review well water quality and yield; identify system locations and access; review repair history and maintenance; confirm requirements for planned improvements; and budget for potential repairs or upgrades.

How I help buyers

As a Los Gatos and Silicon Valley REALTOR®, I help buyers identify important due-diligence questions and coordinate appropriate professional inspections. I do not replace licensed inspectors, engineers, well specialists or environmental health authorities.

Final thoughts

A beautiful hillside home can offer an exceptional lifestyle, but buyers should understand what lies beneath the surface. Evaluating septic systems, water sources, permits and future development options before purchasing can help avoid costly surprises. For guidance buying or selling in Los Gatos, visit Homes with Nadia.

Sources and disclaimer

Official resources: Santa Clara County Department of Environmental Health Rural Real Estate Sales (scceh.org); Santa Clara Valley Water domestic well testing (valleywater.org); West Valley Sanitation District (wvsdca.gov). This article is general education, not engineering, inspection or legal advice. Requirements should be confirmed with the responsible agencies.

About the author

Nadia Kafaipour | REALTOR® | Real Brokerage Technologies, Inc. | CA DRE #02205762. Cover photograph is illustrative and digitally altered; it does not depict a verified Los Gatos listing.