Obtaining a Septic System Permit

Anyone who intends to install a septic system with a flow of less than 10,000 gallons per day must use the following generalized process:  

Click Here to learn about special permit information for Recreational Camps & Cabins

Click Here for special permit requirements and inspections required to reuse an existing septic system.


Site Investigation & Deep Soil Probe Test


The first test on the site is a deep soil probe test. In this test, a backhoe pit is dug as deep as eight feet. The SEO enters this pit to examine the make up of the soil (soil profile). From this, the SEO will determine the suitability of the soil for a septic system.  If the soil is determined suitable for a type of system (standard or alternate), then a percolation test will be performed. If the soil is determined unsuitable, no permit will be issued.


As part of this site investigation, the SEO will determine if the proposed location of the system will meet isolation distance requirements.  The sewage system is required to be certain distances (isolated) from natural and man-made features.  This is done to assure long term operation of the new system and to prevent ground or surface water pollution.  



To attain a suitable location, the SEO  needs to conduct the soils test at certain locations in order to site the system on a specific part of the lot.  The septic system must be isolated from certain features that may be present on the lot in order to protect surface and ground water. These isolation distances are:


1.      Property lines, easements, or right-of-ways:  10 feet

2.      Occupied buildings, swimming pools, and driveways:  10 feet

3.      Water wells or springs:  100 feet

4.      Cisterns used as a water supply:  25 feet

5.      Water lines under pressure:  10 feet

6.      Streams, lakes, ponds, or other surface water:  50 feet

7.      Other septic systems:  5 feet

8.      Surface Drainage ways, storm water basins, and road ditches:  10 feet

9.      Natural or manmade slopes greater than 25%:  10 feet



To prepare a soil profile examination, you will need a backhoe to dig the test pit(s).  The size of the pit will be a maximum of 7 feet deep, and wide enough and tapered on one end so the SEO can get in and out. It is the applicants responsibility to provide the digging of the test pits.


It is best to schedule the backhoe so that all interested parties and the SEO can be at the site at the same time.  In this way, the SEO can evaluate several test pits and choose the best location with the Applicants needs in mind. Also the pits can be backfilled at the same time.

The SEO will identify if a "limiting zone" is present in the soil.


A limiting Zone is any layer in the soil geology which does not renovate sewage or which limits the downward movement of sewage effluent. The most common condition for the denial of an on-lot permit is the formation of hardpans that limit the downward movement of water.  These are identified by dense soil layers that cause shallow perched water tables.
ÜThe type of on lot system permitted at a site is totally dependant upon the depth of suitable soils at a given location.




Soil particles “hold” on to harmful microbes in the sewage allowing beneficial bacterial to breakdown the sewage effluent before it enters a Limiting Zone.

Pennsylvania regulations require that a minimum of 48 inches of well aerated soil of suitable texture and structure are necessary for adequate renovation of sewage effluent.  If soil conditions are acceptable sand is often added to the ground surface to achieve this 48 inches of soil. (sandmounds)


In Pennsylvania there must be at least 10 or 20 inches of suitable soils material from the soil surface to the “limiting zone” to qualify as acceptable for an on-lot septic system.  When the site investigation and soil evaluations are acceptable, a percolation test may be conducted.


Knowing the Types of On-Lot Systems

Determined by the above soils testing, there are three basic conventional on-lot systems permitted for use on residential lots. They are:


                Depth of Suitable Soil                        Type of System Permitted

Less than 10”                                                Unsuitable

10” to 20”                                               Alternate Systems

 20” to 48”                                           Elevated Sandmounds

 48” to 60”                                         At-Grade Seepage Beds

60” – Plus                                Conventional Gravity Trenches and/or Beds    


The type of system selected and permitted depends on site conditions and the type of soils on the lot.

Choosing an Alternate System

In some cases, when a lot does not qualify for a regular on-lot disposal system, the lot owner may wish to consider an alternate system. There are several alternate methods DEP has approved over the years that may be appropriate. Keep in mind, however, some lots just are not suitable for any type of disposal system due to inadequate soils, high water table, or other important factors.  Also, these alternates systems are considered to be rather expensive.  




The Percolation Test

A percolation ("perc") test is a method that measures the rate at which water moves through soil. The test is used to determine the rate in which the soil will allow water to drain quickly enough to support a properly working septic system. The size of the soil absorption area (leech field or sandmound) is based on these test results.  The following site preparation is required to perform a percolation test:



If the site investigation, soil profile and percolation tests indicate that an acceptable area for the system exists, the SEO will advise the applicant that the site is suitable and that the applicant needs to have a septic system designed.  The system designer, usually another SEO from a neighboring municipality, must consider the site condition, limiting zone, percolation test results, and the number of bedrooms proposed in the home when designing the system.  Additionally certain sites require a detailed engineering design or a may require a design by a registered professional engineer.

Additional information is also available at the DEP website: Pennsylvania Department of Environmental Protection