Septic Systems in Pennsylvania

67 counties · ~25% of homes on septic · ~662,575 septic systems

State Regulation Overview

Regulatory Body
Pennsylvania DEP
Inspection Required for Sale
Yes
Nitrogen Reduction Areas
No
Advanced Treatment Areas
Yes

Seller must provide septic inspection. County-level Sewage Enforcement Officers (SEOs).

Top Counties by Septic Systems

Montgomery County
~25,697 septic homes
Philadelphia County
~24,378 septic homes
York County
~22,822 septic homes
Dauphin County
~21,537 septic homes
Berks County
~21,442 septic homes

All Counties in Pennsylvania

Adams County
104K pop · ~18.8% septic
Allegheny County
1251K pop · ~3.8% septic
Armstrong County
66K pop · ~25% septic
Beaver County
168K pop · ~18.8% septic
Bedford County
48K pop · ~30% septic
Berks County
429K pop · ~12.5% septic
Blair County
123K pop · ~18.8% septic
Bradford County
60K pop · ~25% septic
Bucks County
647K pop · ~7.5% septic
Butler County
194K pop · ~18.8% septic
Cambria County
133K pop · ~18.8% septic
Cameron County
5K pop · ~40% septic
Carbon County
65K pop · ~25% septic
Centre County
158K pop · ~18.8% septic
Chester County
534K pop · ~7.5% septic
Clarion County
37K pop · ~30% septic
Clearfield County
81K pop · ~25% septic
Clinton County
37K pop · ~30% septic
Columbia County
65K pop · ~25% septic
Crawford County
84K pop · ~25% septic
Cumberland County
259K pop · ~18.8% septic
Dauphin County
286K pop · ~18.8% septic
Delaware County
577K pop · ~7.5% septic
Elk County
31K pop · ~30% septic
Erie County
271K pop · ~18.8% septic
Fayette County
129K pop · ~18.8% septic
Forest County
7K pop · ~35% septic
Franklin County
156K pop · ~18.8% septic
Fulton County
15K pop · ~35% septic
Greene County
36K pop · ~30% septic
Huntingdon County
44K pop · ~30% septic
Indiana County
83K pop · ~25% septic
Jefferson County
44K pop · ~30% septic
Juniata County
24K pop · ~30% septic
Lackawanna County
216K pop · ~18.8% septic
Lancaster County
553K pop · ~7.5% septic
Lawrence County
86K pop · ~25% septic
Lebanon County
143K pop · ~18.8% septic
Lehigh County
375K pop · ~12.5% septic
Luzerne County
326K pop · ~12.5% septic
Lycoming County
114K pop · ~18.8% septic
McKean County
40K pop · ~30% septic
Mercer County
111K pop · ~18.8% septic
Mifflin County
46K pop · ~30% septic
Monroe County
168K pop · ~18.8% septic
Montgomery County
857K pop · ~7.5% septic
Montour County
18K pop · ~30% septic
Northampton County
313K pop · ~12.5% septic
Northumberland County
92K pop · ~25% septic
Perry County
46K pop · ~30% septic
Philadelphia County
1604K pop · ~3.8% septic
Pike County
59K pop · ~25% septic
Potter County
16K pop · ~30% septic
Schuylkill County
143K pop · ~18.8% septic
Snyder County
40K pop · ~30% septic
Somerset County
74K pop · ~25% septic
Sullivan County
6K pop · ~35% septic
Susquehanna County
38K pop · ~30% septic
Tioga County
41K pop · ~30% septic
Union County
43K pop · ~30% septic
Venango County
50K pop · ~25% septic
Warren County
39K pop · ~30% septic
Washington County
209K pop · ~18.8% septic
Wayne County
51K pop · ~25% septic
Westmoreland County
355K pop · ~12.5% septic
Wyoming County
26K pop · ~30% septic
York County
456K pop · ~12.5% septic

Septic Systems in Pennsylvania

Approximately 25% of homes in Pennsylvania rely on septic systems for wastewater treatment, totaling an estimated 662,575 septic systems across the state's 67 counties. This places Pennsylvania among the states with significant decentralized wastewater infrastructure.

Septic Regulations in Pennsylvania

Septic regulations in Pennsylvania are administered by Pennsylvania DEP, with permits typically issued at the county level through local health departments. Requirements for tank sizes, setback distances, approved system types, and inspections can vary significantly between counties.

Pennsylvania requires septic system inspections as part of real estate transactions. Sellers must demonstrate that their septic system is functioning properly before a property sale can close. This typically involves hiring a licensed inspector to evaluate the tank, distribution box, and drainfield.

Common Septic System Types

Homeowners in Pennsylvania typically use one of several septic system types depending on local soil conditions: conventional gravity-fed systems where soil percolation is adequate, pressure distribution systems in areas with moderate limitations, mound systems where shallow bedrock or high water tables prevent conventional installation, and aerobic treatment units (ATUs) in environmentally sensitive areas.

Septic Maintenance Requirements

The EPA recommends pumping septic tanks every 3 to 5 years, though the exact frequency depends on tank size, household size, and water usage. In Pennsylvania, some counties have adopted mandatory pumping schedules or maintenance tracking programs. Proper maintenance prevents costly repairs, protects groundwater quality, and extends the lifespan of the drainfield — the most expensive component to replace.

Select a county above to view detailed septic regulations, estimated costs, soil suitability data sourced from the USDA NRCS Soil Survey, and groundwater depth measurements from the USGS.

Data last updated: 2026-04-13