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
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
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.
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.
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.
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: 