Septic Engineer in Auburn, NY

Septic design around Auburn, in two sentences

The city of Auburn itself is on public sewer, so a septic engineer is mostly needed on the lots just outside it: the rural roads of the surrounding towns, older homes the city mains never reached, and new houses on land with no sewer frontage. On those lots, Cayuga County will not accept a new septic system unless a design professional has run the perc tests and deep hole, drawn the plan, and signed it.

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, so you have one written estimate and one schedule instead of three separate hires.

Sewer inside the city, septic just past it

The City of Auburn runs its own sewage treatment plant, and its city code ties connection to the public main. Several neighboring towns buy sewer service through a wholesale agreement with the city: Sennett town records list Sennett, Fleming, Owasco and Aurelius as parties to that agreement along with Auburn. That covers the developed districts. It does not cover every farm road, lake lot or new split off a parent parcel, and those are the properties that end up on our list.

If your lot is close to a sewer district line, find out first whether a main is available and accessible. Cayuga County reviews septic plans for lots without that option; when a main is close, the town or district usually wants the connection instead.

Auburn area soils and what they push the design toward

Auburn sits at the north end of Owasco Lake on glacial till and drumlins. The uplands are mostly Honeoye silt loam, which the USDA soil survey describes as very deep and well drained, formed in loamy till. Those are the lots where a conventional trench system usually has a shot, because Appendix 75-A wants at least four feet of usable soil above rock, unsuitable soil and the high seasonal water table for a conventional absorption field.

The swales between the drumlins are a different story. Lima silt loam is moderately well drained, and Kendaia silt loam is somewhat poorly drained, sitting in footslopes and drainageways. Toward the Owasco Outlet and the low ground near the lake, Canandaigua silty clay loam is poorly to very poorly drained. On those soils the deep hole tends to show mottling or water inside the top two to three feet, and the plan shifts to a shallow trench system (two to four feet of usable soil), a raised system, or a mound.

The higher drumlin crests can bring rock up closer to the surface. When the deep hole hits rock inside two feet, a raised system built in imported fill is often the answer the state code allows.

How it works in Auburn

1. Send the address and what you are building. Bedrooms matter most. New construction is sized at 110 gallons per day per bedroom under Appendix 75-A. You get a written estimate in 1 hour.
2. Perc tests and deep hole. The county instructions say the design professional must perform a perc test and a deep test hole evaluation before preparing plans. The state code calls for at least two perc tests and a test hole at least six feet deep in or next to the leach area.
3. PE stamped plan. The plan shows the tank, distribution, absorption area, the 50 percent reserve area, wells on your lot and the neighbors, and every watercourse and wetland.
4. Cayuga County submittal. Three copies go to the Environmental Health Division at 8 Dill Street, Auburn, with the application and the $150 review fee. A county inspector checks the property for wetlands, watercourses, wells and the perc holes.
5. Acceptance and building permit. When the plan complies with Appendix 75-A, two accepted copies come back with a certificate of acceptance, and the county sends a memo to the town Code Enforcement Officer so the building permit can move.
6. Install and verification. The county does not inspect before backfill. The design professional verifies the work before it is covered and files a certificate of construction letter, and the contractor files a second certificate. Then the town can issue the certificate of occupancy.

What the Cayuga County Health Department checks

• That the plan was prepared and signed by a Licensed Professional Engineer or Registered Architect, with perc and deep hole data attached.
• Separation distances from Appendix 75-A Table 2: an absorption field 100 feet from a well, 100 feet from a stream, lake or wetland, 20 feet from the house and 10 feet from the property line. A septic tank needs 50 feet from a well.
• Septic tank size by bedroom count: 1,000 gallons for one to three bedrooms, 1,250 for four, 1,500 for five.
• Usable soil depth and seasonal high groundwater against the system type chosen.
• Slope, since slopes over 15 percent are unacceptable for onsite systems under 75-A.4, and flood level, since land below the 10 year flood level is out.

Common Auburn area problems and the design fix

Timeline

Testing and the stamped plan are the first stretch. The county application says approval to construct may take up to 4 to 6 weeks after submittal. The install itself is usually days on site. An accepted plan expires two years after acceptance on the county repair form, so plan the build inside that window.

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)
• Cayuga County, Owasco Watershed Rules and Regulations update project
• Owasco Lake Watershed Rules and Regulations, Updates 2023 (State Recommendations dated 9/15/23)
• 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, Canandaigua
• Town of Sennett Town Board minutes, July 21, 2022 (sewer agreement with the City of Auburn)
• NYSDEC Environmental Notice Bulletin, City of Auburn Sewage Treatment Plant

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.