NH's Septic Design Process

What's Involved In Having A Septic System Designed In New Hampshire

As of April 16, 2011 “Repair in Kind” is no longer allowed. All work involving the “Effluent Disposal Area” (EDA) requires a Septic Design. Septic Tanks are allowed to be repaired or replaced with a tank of the same size or larger and in the same location as the existing tank. Tank must be sealed water tight to prevent groundwater infiltration and effluent leakage. The pipe inlet & outlet are to have rubber gaskets.

The NH Licensed Septic Designer will access your site and mark areas for test pits to be dug. The marked area must meet state and municipal setbacks and requirements.

Designer will contact Dig Safe to mark underground utilities. Dig Safe has 3 business days to mark utilities.

Many towns require a form and/or fee, in order to book a test pit time with the town inspector. Once test pits have been staked, town requirements should be taken care of, so test pits can be dug as soon as Dig Safe is cleared.

Designer will coordinate with the town inspector & backhoe to dig test pits. A test pit needs to be large enough for the Designer to fit in, so to see the soil profile and log its characteristics.

* Note: Test pits determine the requirements for the design. It is strongly advised that you or your representative be present on-site. It is important in order for you to understand the design needs. You will also be able to ask questions while both the Town representative and your Designer are on-site with the test pit open.

Any Very Poorly Drained soils (VPD), Poorly Drained soils (PD), Wetlands, or Water Features need to be identified and flagged by a Certified Wetland Scientist or Certified Soil Scientist.

A topographic survey will be done for 75 feet to a 100 feet around the proposed Individual Subsurface Disposal System (ISDS). It will identify relevant objects and elevations. A Benchmark (BM) will be set and Tie points established which will allow the Installer to install the EDA according to the approved plan.

It will also allow the State Inspector to easily confirm in the field that the approved plans were followed.

* Note: A topographic survey is Not a Boundary Survey. No deed research is being done. If there is no monumentation or if the lot is tight, a Boundary Survey may need to be done by a NH Licensed Surveyor.

Once all the field work & data has been obtained, your designer will draft plans showing test pit data, design intent, system components with relative inverts & specifications, a plan view, and other information about the lot that the state and town require.

Your designer will provide you with a submittal package consisting of 3 plan sets for the state (NH-DES), the number of plan sets required by your town, a stamped envelope addressed to NH- DES Subsurface Bureau (so plan can be mailed directly from town to state), and a completed state application form.

You need to sign the Front and Back of the application form. Bring the Submittal Package, Signed Application, check payable to NH-DES for $300, and any Town Fees due to the town. If town review is not required, mail the package, application & check directly to the state.

The state technically has 15 business days to process the design, and to approve, deny, or ask for additional information. Most of the time, this process is much quicker.

Other Septic Concerns To Keep In Mind:

Does your contract price include: o Mileage, prints, postage, mailer, etc.

Does your Designer come to you for all stages?

NH Licensed Surveyor, if needed, is usually an additional expense and extra time.

Wetland issues can require additional permitting:

Tidal Buffer: within 100 feet of tidal waters.
Shoreland Permit: within 250 feet of 4th Order streams, Great ponds, Lakes, Ocean, etc.
Dredge & Fill: to cross wetlands to access the site.
Including other Site-work with Septic.

Wetland Permitting can slow the process and add an additional 3 months to a year or more.

Holding Tanks are almost never approved, now that Aeration Pretreatment is available.

It is important to use fully licensed & insured professionals for design & installation.