Canandaigua Lake Septic Inspections: Rules at Sale & 5-Year

Last reviewed: October 9, 2026. General information only, not legal or engineering advice. Each Canandaigua Lake town adopted its own version of the model septic law, and provisions vary. Confirm current requirements with the Watershed Inspector and your town before you list, buy, or build.

Canandaigua Lake is a public drinking water source, and that shapes the septic rules around it more than almost anything else. The Ontario County Soil & Water Conservation District describes the lake as a drinking water source for more than 70,000 people. Because of that, there are three layers of rules for a septic system near the lake: a decades-old state watershed regulation, a watershed inspection program run on behalf of the water suppliers, and town laws based on a model law the watershed communities developed together.

If you’re buying or selling a house that isn’t on public sewer, here’s how those layers fit together.

Layer 1: The state’s Canandaigua Lake watershed rules

New York’s sanitary code has a section written specifically for this lake: 10 NYCRR §132.1. It applies to Canandaigua Lake and every watercourse that drains into it, to protect the public water supplies of the City of Canandaigua, the Villages of Palmyra and Newark in Wayne County, and the Village of Rushville. Among other things, it:

prohibits sewage from being discharged into the lake or any watercourse;
bars privies and sewage receptacles within 100 feet of the lake or a watercourse in Zone I (the lake shores and most of the watershed), and within 50 feet of watercourses in Zone II (the West River drainage), with narrow exceptions for watertight receptacles where the distance can’t be met;
requires written permission from the watershed authority, with plans and a percolation test, before installing, repairing, or replacing a septic system elsewhere in the watershed; and
sets a minimum capacity of 500 gallons for any new or replacement septic tank in the watershed.

These rules are old (the regulation cites 1953 amendments to the Public Health Law), but they are still on the books and still enforced through the inspection program described next.

Layer 2: The Canandaigua Lake Watershed Inspection Program

The Canandaigua Lake Watershed Commission is made up of the five municipal water purveyors that withdraw and sell lake water: the City of Canandaigua, the Town of Gorham, the Village of Newark, the Village of Palmyra, and the Village of Rushville. State public health law charges the Commission with enforcing the watershed rules. The Ontario County SWCD administers the Commission’s inspection program and employs the Canandaigua Lake Watershed Inspector.

According to the SWCD, the Watershed Inspector’s responsibilities include:

inspecting septic and alternative systems at the time of property deed transfer, and periodically for certain shoreline properties;
coordinating the model onsite wastewater law (effective January 1, 2018) as individual towns adopt it;
consulting on new construction and repairs, and reviewing building plans for wastewater suitability;
conducting deep hole and percolation tests for new system placement; and
keeping records of individual systems throughout the watershed and tracking maintenance of alternative systems such as aerobic treatment units.

The SWCD posts a Canandaigua Lake Watershed inspection request form, and its septic programs page has an address lookup that tells you whether a property falls under the watershed program or the county’s Uniform Procedures Program.

Layer 3: Town septic laws based on the model law

In 2016, after more than a year of work by a joint workgroup of town officials, county planners, code officers, and the watershed organizations, the Canandaigua Lake Watershed Council endorsed a Model Onsite Wastewater Treatment System Law. Because New York is a home rule state, each town decided whether and how to adopt it. The Council notes the towns of Canandaigua, Gorham, Middlesex, Italy, Naples, and South Bristol were represented in the workgroup. The SWCD cautions that actual provisions may vary from one municipality to the next.

The model law is still the best map of what to expect. Its main provisions:

Inspection before a sale

The owner must arrange a septic inspection by a Certified Inspector before conveying the property. The inspection must be completed at least 10 days before the transfer, and the report must be filed with the authority having jurisdiction, the current owner, and the proposed new owner before the transfer. Skipping it is a violation, and the town can then inspect after closing.

Other triggers

An inspection is also required before a change of use, before adding bedrooms or bedroom equivalents, before increasing a building’s square footage by more than 25 percent, and before alterations where the work area exceeds 50 percent of the existing building.

Five-year inspections within 200 feet of the lake

Systems whose absorption area or holding tank is wholly or partly within 200 feet of Canandaigua Lake must be inspected every five years by a Certified Inspector. The Watershed Inspector notifies owners by January 15 of their inspection year, and the inspection is due by December 31. If there’s no stamped as-built drawing showing the absorption area’s location, the first inspection is done by the Watershed Inspector, and owners whose absorption area turns out to be more than 200 feet away can be exempted from future cycles in writing. An inspection between cycles resets the five-year clock.

Design standards near the lake

The model law sets a higher design flow for systems wholly or partly within 200 feet of the lake (150 gallons per day per bedroom, versus 130 farther away) and sizes systems by both bedrooms and heated square footage. It also lists conditions that make a system “substandard,” such as no watertight tank before the absorption area, or a tank that needs pumping more than four times a year.

Holding tanks and treatment units

Holding tanks must have a float switch and an audible and visual high-level alarm, and owners must keep pump-out records. Enhanced treatment units need ongoing maintenance and inspection reports.

A sample timeline for a sale

Every transaction is different, but under the model law a smooth septic process for a lakeside sale usually looks like this:

Listing: the seller gathers the system’s records (as-built drawing, past inspections, pump-out receipts) and confirms which town law applies.
Under contract: the seller arranges the inspection with an inspector the town accepts, leaving time for pumping, uncovering components, and any follow-up.
At least 10 days before closing: the inspection is complete and the report is filed with the town, the seller, and the buyer.
If problems turn up: the parties negotiate repairs, escrow, or price, and the buyer learns what a replacement would require near the lake.
After closing: the new owner notes when the next five-year inspection is due if the absorption area is within 200 feet of the lake.

Owning a system near the lake

The model law also limits what you can do on top of the absorption area: no buildings, paving, trees or shrubs, fill, vehicle parking or crossing, above-ground pools, or driveways. It prohibits discharging anything but sewage into the system; roof, cellar, foundation, and storm drainage must be kept out. New systems and modifications must be designed by a Design Professional. These are good practices anywhere, but near Canandaigua Lake they’re written into law.

Routine pumping, keeping grease and wipes out of the system, spreading out laundry loads, and fixing running toilets all reduce the chance of a failure that becomes a violation and an expensive replacement.

What this means if you’re buying

Find out which town law applies and get a copy. The model law is a guide, not the law in your town.
Ask the seller early for the last inspection report, the as-built drawing, pump-out records, and any notices from the Watershed Inspector.
Schedule the inspection well ahead of closing. The 10-day requirement is a minimum.
Count bedrooms the way the law does. Rooms that function as bedrooms can count, even if the listing calls them dens or offices.
Plan for the five-year cycle if the absorption area is within 200 feet of the lake.
Negotiate repairs in writing. Failed systems near the lake can face specific replacement requirements.
Ask about funding. New York’s State Septic System Replacement Fund reimburses eligible owners in participating counties up to 50 percent of costs (capped at $10,000), or 75 percent (capped at $25,000) for enhanced systems, per its December 2025 program outline. Ask Ontario or Yates County whether your property qualifies.

Common questions

Is the Watershed Inspector the only one who can inspect at sale?

The model law refers to a “Certified Inspector” for transfer inspections and gives the Watershed Inspector specific roles. Which inspectors your town accepts depends on its adopted law. Ask the town or the SWCD.

Does any of this apply to the Yates County side?

Yes. The watershed rules in 10 NYCRR §132.1 cover the whole drainage area, including the Yates County towns of Italy and Middlesex. Town laws vary.

What about Keuka Lake?

Keuka has its own cooperative program. See our sister site’s Keuka Lake septic inspection guide.

Official sources

Spot something out of date? Tell us.