Frequently Asked Questions

Why is a site investigation important?

Approval of subsurface sewage disposal systems is one of the most important functions of local health departments. A site investigation determines the size, location and depth into grade thus protecting ground water and well water from contaminates. A key element in enforcing this part of the public health code is the percolation test, as well as the observations for ground water levels and ledge rock conditions. Walking over the site, studying soil maps, and observing and feeling the texture of the soils may be helpful, but they cannot replace the percolation test and the observation pit. The essential parts of the site investigation are as follows:

Soil testing is necessary to determine the size of the leaching system. Tests must be made in the area of the proposed leaching system and at the depth of the leaching system.
Soil testing is also necessary to determine if the seepage rate is slower than one inch in thirty minutes, in which case a qualified professional engineer must prepare plans.
An observation pit is necessary to determine if high ground water is present within 36” of the surface of the ground, a restrictive layer is within 36” of the surface of the ground or there is seasonal high groundwater; in which case a qualified professional engineer must prepare plans. Areas of special concern are detailed in the technical standards of the Public Health Code [see section 19-13-B103d] subsection (e) disposal of sewage in areas of special concern.
An observation pit is necessary also to determine if fill has been added over an impervious soil such as muck, clay, hardpan, or ledge rocks.
Test for the seepage rate, ledge rock, and maximum ground water levels are the basis in determining if the lot is satisfactory for a sewage disposal system and the size of leaching area needed. Before a building permit is issued, the actual test and observation must be carried out. A sewage disposal system design plan must be submitted to and approved by the Northeast District Department of Health. Once the design plan is approved a septic permit will be issued by NDDH and the building permit can be secured from your building official with approval.

When do I need a B-100a?

The Connecticut Public Health Code requires the Northeast District Department of Health to review and approve all residential and commercial plans for additions or structural changes to existing properties (B-100a) that are more than 200 SQFT. This includes the installation of above ground swimming pools. A B-100a should be filed in order to:

Protect your property
Prevent mistaken use of septic repair repair area
Identify area to repair septic system
Avoid placement of additions next to septic system or well
Protect your septic system or well from costly repairs
Prevent mistakes that could cause community wide sewage disposal problems
Avoid serious pollution problems

How do I file a B-100a?

Contact NDDH for an application or download from our forms and applications section. Complete and submit the application with:

$30 fee for review of plan and application, and related research that is typically required
Plot plan drawn to scale (1"=200 ft or 1"=30 ft) showing house, well, septic, and proposed addition with a written description of what the addition will be.