Septic Engineer and Perc Test in Sennett, NY
Sennett buys sewer service from Auburn for its districts. Outside them, homes run on septic. We run the perc test, coordinate the PE stamped design and install it.
Fees. Process. Answers.
Septic design for lots in the Town of Sennett.
Sennett has sewer service through a wholesale agreement with the City of Auburn, per town board minutes. Properties outside the served areas use septic systems reviewed by Cayuga County.
How fast the soil takes water, in minutes per inch. Appendix 75-A uses it to set the trench length. Soil faster than 1 minute per inch or slower than 60 is outside the conventional trench table.
The county instructions say the design professional must perform the perc test and the deep test hole evaluation before preparing the plans.
The Cayuga County Health Department, Environmental Health Division, 8 Dill Street, Auburn, NY 13021, (315) 253-1405.
1,250 gallons minimum under Appendix 75-A Table 3.
$150 for a new system plan, per the county application revised January 7, 2025.
Send the address and bedrooms through the form. Estimate in 1 hour.
Sennett septic, answered first
The Town of Sennett gets sewer service through a wholesale agreement with the City of Auburn; town minutes from 2022 list Sennett, Fleming, Owasco, Aurelius and Auburn as the parties. The rest of the town, the farm roads and new splits toward the Onondaga County line, is on septic, and Cayuga County will not accept a new system without a plan prepared and signed by a design professional who ran the perc and deep hole tests first.
Designs are prepared and stamped by a New York licensed Professional Engineer (PE). Backwell coordinates the design, the Cayuga County Health Department submittal, and the install.
What the perc test is really deciding
A perc test times how fast water drops in a soaked hole, in minutes per inch. Appendix 75-A turns that number into a trench length. At 1 to 5 minutes per inch the application rate is 1.20 gallons per day per square foot; at 46 to 60 it drops to 0.45. A three bedroom house at 110 gallons per bedroom is 330 gallons per day, so the same house can need well under half the trench in fast soil that it needs in slow soil.
The deep hole matters as much. A conventional field needs four feet of usable soil over rock, tight soil and seasonal high water, with two feet under the trench bottom. Two to four feet of usable soil points to a shallow trench system. One to two feet over rock or tight soil, with water at least a foot down, points to a raised system in fill.
Sennett soils
Sennett is drumlin and till country east of Auburn. The common upland soil in this part of Cayuga County is Honeoye silt loam, very deep and well drained, with Lima silt loam, moderately well drained, on gentler slopes. Kendaia silt loam sits in footslopes and drainageways and is somewhat poorly drained, and Lyons silt loam fills the depressions, poorly to very poorly drained. The field almost always goes on the drumlin side of a Sennett lot when the lot has one.
How it works in Sennett
- Address and bedrooms. Estimate in 1 hour.
- Is there sewer? If a district main is available, the town or district usually wants the connection. If not, septic it is.
- Perc and deep hole. Two or more perc tests, a six foot hole, more holes where the profile changes.
- PE stamped plan. Tank by bedroom count, field by perc rate, reserve area drawn.
- Cayuga County review. Three copies, application and $150 fee to 8 Dill Street, Auburn.
- Permit, build, certify. The county notifies the Sennett Code Enforcement Officer, the system is built, and the PE files the certificate of construction before backfill is closed out.
What the county checks
- Septic tank capacity: 1,000 gallons for one to three bedrooms, 1,250 for four, 1,500 for five, 1,750 for six.
- Minimum 4 feet of undisturbed soil between trenches, trench depth no more than 30 inches, trenches parallel to the contours.
- Distribution box with a removable cover within 12 inches of grade, or an extension to grade.
- Wells on adjacent lots shown on the plan, not just your own.
Sennett problems and fixes
Perc too slow
Slower than 60 minutes per inch is outside the trench table. If faster soil sits under the tight layer with three feet available, a cut and fill system replaces the tight layer. Otherwise a raised system builds the field in fill.
Bedroom addition
The tank and field are sized to bedrooms, and an expansion attic counts as one. More bedrooms can mean a bigger tank and more trench.
Buying a lot to build on
Testing before closing tells you which system type the lot supports and roughly how much ground the field and reserve take.
Timeline
Testing, then design, then up to 4 to 6 weeks for county approval to construct, per the 2025 county application, then the install.
Sources
- NYS DOH, 10 NYCRR Appendix 75-A, Wastewater Treatment Standards, Residential Onsite Systems
- Cayuga County Health Department, Septic System Installation and Inspection
- Cayuga County Health Department, Instructions to Obtain Septic System Plan Approval for New Construction
- Cayuga County Health Department, Application to Install a New Septic System (rev. 1/7/2025)
- Cayuga County Health Department, Application to Modify/Replace an Existing Septic System (rev. 1/7/2025)
- Town of Sennett Town Board minutes, July 21, 2022
- USDA NRCS Official Soil Series Description, Honeoye
- USDA NRCS Official Soil Series Description, Lima
- USDA NRCS Official Soil Series Description, Kendaia
- USDA NRCS Official Soil Series Description, Lyons
Rules and fees as published by each office on the date this page was written. They can change; the design is checked against the current versions at submittal.
More around Sennett.
Nearby towns
Septic engineer in AuburnSeptic engineer in OwascoSeptic engineer in WeedsportSeptic engineer in Port ByronDesign and site problems
Conventional septic designRaised bed septic designClay soilFailed perc testPressure distribution designTell us about the Sennett property.
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