Septic Systems in Plymouth County, MA

Regulations, costs, soil data & local providers

Pop. 530,819 ~5.1% on septic ~10,829 septic homes Well drained soil

Septic pumping in Plymouth County, Massachusetts costs $450-$900 (avg $650). A new septic system installation costs $9,250-$18,500. USDA soil data rates 0.9% of county soils as suitable for septic absorption fields. Approximately 10,829 homes in this county use septic systems.

Septic System Costs in Plymouth County

ServiceLowAverageHigh
Pumping / Cleaning$450$650$900
Routine Inspection$350$500$700
Real Estate Inspection$650$900$1250
Minor Repair$1,150$1,650$8,100
Conventional Installation$9,250$13,200$18,500
Aerobic System Installation$17,300$24,750$34,650
Drainfield Replacement$9,250$13,200$18,500
Perc Test$1,400$2,000$2,800

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

Soil & Septic Suitability in Plymouth County

Drainage Class
Well drained
Hydrologic Group
A
Unique Soil Types
72
Avg Bedrock Depth
1.5 ft

Dominant Soil Types

Soil SeriesCoverageDrainageHydro Group
Plymouth 1401 Excessively drained A
Canton 1369 Well drained B
Carver 1118 Excessively drained A
Barnstable 1017 Well drained B
Montauk 746 Well drained C

Septic Tank Absorption Field Suitability

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

Not Limited (Good)0.9%
Somewhat Limited1.9%
Very Limited97.2%

Overall rating: Very limited

Source: USDA NRCS Soil Survey Geographic Database (SSURGO)

Groundwater & Water Table in Plymouth County

Monitoring Wells
24
Avg Depth to Water
13.2 ft
Median Depth
9.9 ft
Shallowest Recorded
3.1 ft Shallow Risk

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

Source: USGS National Water Information System. Based on 1113 measurements from monitoring wells.

Septic Regulations & Permits in Plymouth 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 Plymouth County health department for current permit requirements, fees, and approved system types.

Septic System FAQ for Plymouth County

How much does septic pumping cost in Plymouth County?
Septic pumping in Plymouth County, Massachusetts typically costs between $450 and $900, with an average of $650. 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 Plymouth County?
A conventional septic system installation in Plymouth County typically costs $9,250-$18,500. An aerobic treatment unit (ATU) costs $17,300-$34,650. Given the predominantly well 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 Plymouth 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 Plymouth County health department for current requirements and fees.
What soil types are in Plymouth County and how do they affect septic systems?
Plymouth County has predominantly Plymouth, Canton, Carver soils. The dominant drainage class is Well drained with hydrologic group A. The USDA rates 0.9% of surveyed soils as "Not Limited" for septic absorption fields, 1.9% as "Somewhat Limited", and 97.2% as "Very Limited".
Is a septic inspection required when selling a home in Plymouth 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 $900. 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 Plymouth 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. With approximately 10,829 septic systems in Plymouth County, there are many local providers offering regular pumping services.
Can I install a conventional septic system in Plymouth County?
It depends on your specific site. USDA soil data shows that 97.2% of soils in Plymouth County are rated "Very Limited" for septic absorption fields, while only 0.9% 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 ($1400-$2800) and soil evaluation are required before the county will approve a system design.
How long does a septic system last in Plymouth County?
A well-maintained septic system in Plymouth 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 (Plymouth County has predominantly well 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

Population530,819
Est. Septic Homes10,829
Avg Pumping Cost$650
Drainage ClassWell drained
Septic SuitabilityVery limited

Common Septic Services

Pumping: $450-$900
Inspection: $350-$700
Repair: $1,150-$8,100
Installation: $9,250-$18,500

Data last updated: 2026-04-13