Septic Systems in Nantucket County, MA

Regulations, costs, soil data & local providers

Pop. 14,255 ~23.8% on septic ~1,357 septic homes Excessively drained soil

Septic pumping in Nantucket County, Massachusetts costs $400-$750 (avg $550). A new septic system installation costs $7,950-$15,900. USDA soil data rates 0% of county soils as suitable for septic absorption fields. Approximately 1,357 homes in this county use septic systems.

Septic System Costs in Nantucket County

ServiceLowAverageHigh
Pumping / Cleaning$400$550$750
Routine Inspection$300$450$650
Real Estate Inspection$550$800$1100
Minor Repair$1,000$1,400$6,950
Conventional Installation$7,950$11,350$15,900
Aerobic System Installation$14,900$21,300$29,800
Drainfield Replacement$7,950$11,350$15,900
Perc Test$1,200$1,700$2,400

Cost estimates based on regional market data for Nantucket County, Massachusetts. Actual costs depend on system type, site conditions, and provider.

Soil & Septic Suitability in Nantucket County

Drainage Class
Excessively drained
Hydrologic Group
A
Unique Soil Types
32

Dominant Soil Types

Soil SeriesCoverageDrainageHydro Group
Evesboro 483 Excessively drained A
Riverhead 247 Well drained A
Woodbridge Variant 183 Moderately well drained C
Katama 180 Well drained A
Plymouth 176 Excessively drained A

Septic Tank Absorption Field Suitability

USDA NRCS rates soil suitability for septic absorption fields across this county:

Not Limited (Good)0%
Somewhat Limited2.6%
Very Limited97.4%

Overall rating: Very limited

Source: USDA NRCS Soil Survey Geographic Database (SSURGO)

Groundwater & Water Table in Nantucket County

Monitoring Wells
10
Avg Depth to Water
19 ft
Median Depth
19.3 ft
Shallowest Recorded
4.5 ft

Water table depths in this county are generally favorable for conventional septic systems.

Source: USGS National Water Information System. Based on 1292 measurements from monitoring wells.

Septic Regulations & Permits in Nantucket County

State Regulatory Body
Massachusetts DEP
Inspection Required for Home Sale
Yes
Nitrogen Reduction Areas
Yes
Advanced Treatment Required
In designated areas

Title 5 inspection mandatory within 2 years before property sale or 6 months after. Strict Cape Cod nitrogen rules.

Contact the Nantucket County health department for current permit requirements, fees, and approved system types.

Septic System FAQ for Nantucket County

How much does septic pumping cost in Nantucket County?
Septic pumping in Nantucket County, Massachusetts typically costs between $400 and $750, with an average of $550. Costs vary by tank size (1,000-1,500 gallons is typical), ease of access, distance from the pumping company, and how full the tank is. Most homeowners should pump their tank every 3-5 years.
How much does a new septic system cost in Nantucket County?
A conventional septic system installation in Nantucket County typically costs $7,950-$15,900. An aerobic treatment unit (ATU) costs $14,900-$29,800. Given the predominantly excessively drained soils in this area, some sites may require alternative system types. Costs include the tank, drainfield, permits, and labor.
Do I need a permit for a septic system in Nantucket County?
Yes. Virtually all counties in Massachusetts require a permit before installing, repairing, or replacing a septic system. The permit process typically involves a soil evaluation or percolation test, system design by a licensed professional, application to the county health department, and one or more inspections during installation. Contact the Nantucket County health department for current requirements and fees.
What soil types are in Nantucket County and how do they affect septic systems?
Nantucket County has predominantly Evesboro, Riverhead, Woodbridge Variant soils. The dominant drainage class is Excessively drained with hydrologic group A. The USDA rates 0% of surveyed soils as "Not Limited" for septic absorption fields, 2.6% as "Somewhat Limited", and 97.4% as "Very Limited".
Is a septic inspection required when selling a home in Nantucket County?
Yes. Massachusetts requires a septic system inspection as part of the property transfer process. This typically involves a certified inspector evaluating the tank, drainfield, and all system components. The inspection cost in this area averages $800. If the system fails inspection, repairs or replacement may be required before the sale can proceed.
How often should I pump my septic tank in Nantucket County?
The EPA recommends pumping your septic tank every 3-5 years for a typical household. The exact frequency depends on tank size, household size, and water usage. A 1,000-gallon tank serving a family of 4 should generally be pumped every 3 years. Some counties in Massachusetts have mandatory pumping schedules — check with your local health department.
Can I install a conventional septic system in Nantucket County?
It depends on your specific site. USDA soil data shows that 97.4% of soils in Nantucket County are rated "Very Limited" for septic absorption fields, while only 0% are "Not Limited." This means many properties will require alternative systems such as mound systems, pressure distribution systems, or aerobic treatment units. A percolation test ($1200-$2400) and soil evaluation are required before the county will approve a system design.
How long does a septic system last in Nantucket County?
A well-maintained septic system in Nantucket County typically lasts 25-30 years, though some components may need attention sooner. The concrete septic tank itself can last 40+ years, while the drainfield — the most critical and expensive component — usually lasts 15-25 years depending on soil conditions (Nantucket County has predominantly excessively drained soils). Regular pumping every 3-5 years and avoiding excess water usage are the two most effective ways to extend system life.

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Quick Facts

Population14,255
Est. Septic Homes1,357
Avg Pumping Cost$550
Drainage ClassExcessively drained
Septic SuitabilityVery limited

Common Septic Services

Pumping: $400-$750
Inspection: $300-$650
Repair: $1,000-$6,950
Installation: $7,950-$15,900

Data last updated: 2026-04-13