Septic systems, sewer lines and excavation across Rhode IslandSeptic and excavation across Rhode Island
Call or text (401) 474-8926 Contractor Reg: 2681 · DEM: L1362
South County Septic & Excavation Services
Septic system design laid out in the ground as rows of leach field modules on a sand bed
Our Services

Septic System Design in North Kingstown, RI

Septic System Design · North Kingstown, RI

Your lot's soil and water table set the design

Septic system design sets where a new system goes on your lot and what kind the soil can carry. Rhode Island's septic rules require written state approval of the plans before a system is built. That approval comes from the Rhode Island Department of Environmental Management (RIDEM). Every septic design starts with the soil on the lot and the water table under it.

South County Septic and Excavation Services designs and installs septic systems across Rhode Island. North Kingstown sits at the center of our service area. We work closely with homeowners and builders, and with engineers when a job calls for one. Because we also handle septic system installation, the plan that goes to RIDEM is the plan we build.

What We Handle

  • Site assessments of the slope, the house, any wells and any wetlands nearby
  • Test holes dug within 25 feet of the planned leach field for the soil evaluation
  • Layouts sized by bedroom count and set back from wells and foundations
  • Leach field designs: trench and stone systems, flow diffusers, Eljen In-Drains and shallow narrow drain fields
  • Advanced and nitrogen-reducing designs, including F.A.S.T., Advantex and Orenco systems and bottomless sand filters
  • Designs for new house lots, and replacement designs for failed systems and cesspools
  • The design package put together for RIDEM review

Request a Septic System Design Quote

Tell us about the septic, sewer, drainage or excavation job and where the property is. We look at the job and put the quote in writing.

What Do the Test Holes Tell a Septic Design?

We start each septic design with a site assessment: the slope, the house, any wells and any wetlands nearby. A leach field within 100 feet of a freshwater wetland or 200 feet of a stream needs RIDEM wetlands approval.

The soil evaluation comes next, and we dig the test holes for it. The rules call for two holes within 25 feet of the planned leach field, one uphill and one downhill. Where the ground allows, each hole goes 5 feet down and the soil is logged to at least 10 feet. RIDEM may send its own staff to witness the test.

When the test holes leave the groundwater depth unclear, the rules call for wet-season readings. Those run January 1 to April 1: three readings or more, at least five days apart. On some wet lots, the design adds a curtain drain to lower the water table. The drain usually has to prove itself through one full wet season, January 1 to April 15.

Conventional or Advanced Treatment on South County Lots

Under the state's rules, seasonal high groundwater must sit at least 2 feet below the original ground. The bottom of the leach field stone needs at least 3 feet of separation above that water. Bedrock or impervious hardpan must sit at least 4 feet down and 5 feet below the stone. On some larger lots, a bottomless sand filter can go where seasonal groundwater sits 18 to 24 inches down.

North Kingstown's most common soil, Merrimac, is sandy outwash that drains fast. Dense till and swamp soils hold water near the surface, so those lots may need fill or a different spot. A raised leach field on a slope may need a retaining wall, kept 25 feet from the stone in most cases.

A conventional system sends the tank's effluent to a standard leach field, and an advanced system treats it further first. In RIDEM's Salt Pond and Narrow River critical resource areas, nearly every new system and repair needs nitrogen-reducing treatment. The Salt Pond area takes in the salt pond watersheds of Charlestown, Narragansett, South Kingstown and Westerly. Advanced systems usually need service once or twice a year from a trained provider.

Septic Design for a Replacement or a Cesspool Conversion

Rhode Island's Cesspool Act puts many replacement designs on a clock. After a sale or transfer, the cesspool must be replaced, or the house tied into sewer, within 12 months. RIDEM's rules treat every remaining cesspool as substandard.

Replacing a failed system or a cesspool usually goes to RIDEM as a repair application. For a home, a repair needs no new soil evaluation unless RIDEM asks for one. The rules ask a repair to meet the standards as far as the lot allows, and RIDEM may relax some. If your system is failing now, septic system repair starts by finding the cause.

When the layout is final, the design package goes to RIDEM for approval. A town cannot issue a building permit until it has the state's written septic approvals. In North Kingstown, a building permit application needs the original septic approval and a site plan that shows the system.

New green treatment tanks for an advanced system on a delivery trailer, septic system design String lines set over a crushed stone leach field bed, septic system design

Ready to get started?

Call or text for a written quote. We work about 40 miles around North Kingstown across all of Rhode Island.

(401) 474-8926
How We Work

How a Job With South County Septic Runs

From the first call or text to the finished work, here is how it goes.

1

Call or Text

Call or text (401) 474-8926 and tell us the town and the job. Photos of the problem or the lot help.

2

We Look at the Job

We come out to see the site and how a machine gets in. On a problem call, we look for the cause first.

3

Your Written Quote

The quote comes to you in writing, with the work spelled out. A septic design goes to the state for approval before the install.

4

We Do the Work

After a Dig Safe (811) call, the utilities mark their buried lines before any machine digs. Then we do the work the quote describes.

5

The Finish

Where we dug, we backfill and grade, and we tell you what we did. A new septic system goes into use once the state issues its Certificate of Conformance.

FAQ

Septic System Design Questions, Answered

Common questions about septic system design around North Kingstown and the rest of Rhode Island. If yours is not here, call or text and ask.

Call (401) 474-8926

Do I need a perc test for a septic system in Rhode Island?
Usually not, because Rhode Island designs rest on a soil evaluation instead. The test holes show the soil layers, and their colors show how high the groundwater rises. The soil category found there, along with the bedroom count, sets the leach field's size. The state's rules call for perc test results only on lots that need no soil evaluation.
How big a septic tank does my house need?
RIDEM's rules size the tank by bedroom count. A home with three bedrooms or fewer needs at least 1,000 gallons, and each added bedroom adds 250. A garbage disposal or a tub of 100 gallons or more each adds another 250 gallons. Every septic tank under the rules has two compartments.
How far does a septic system have to be from a well?
For a home system, the state's rules keep a private drinking water well 100 feet from the leach field. The tank needs 75 feet, and the sewer pipe from the house needs 50. In Category 1 soils, the coarser sands, the leach field distance grows to 150 feet. Some nitrogen-reducing designs qualify for shorter distances.
Does adding a bedroom affect my septic system?
It can, because RIDEM sizes septic systems by bedroom count. Going past the bedroom count in the system's original state approval calls for a new septic application. Cesspools and systems from before April 9, 1968 face a stricter rule. For those, adding a bedroom or a floor means an upgrade, and so does a major renovation.
How long is a septic design approval good for?
RIDEM permits for new construction and alterations expire five years after they are issued. Once building starts on a new house, the foundation and the septic system must both be done within one year. A repair permit is good for one year at most. Soil data from the test holes stay valid for five years.
How much does septic system design cost?
Septic system design is priced lot by lot. A new house and a cesspool conversion follow different parts of the state's rules. Wet ground that needs wet-season readings adds work, and so does a lot that calls for advanced treatment. Call or text (401) 474-8926, and we look at the job and put the quote in writing.
More From South County Septic

Work That Pairs With Septic System Design

Sewer line repair pit with new green PVC pipe and fittings joined to the old line

Sewer Line Repair

We dig up and replace broken and root-filled sewer lines, from the house to the street or the septic tank. We also lay new sewer lines for homes that tie into town sewer.

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Water line repair with a backhoe digging at the curb and new blue pipe laid out

Water Line Repair

We find and fix leaking or broken water lines between the street or the well and your house. We also lay new water lines for new homes.

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Drain cleaning camera inspection fed through a cleanout with the monitor beside it

Drain Cleaning

We clear clogged drains and main lines, and we cut tree roots out of the pipe. A camera inspection then shows what caused the clog.

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Why Choose South County Septic

Septic, Sewer and Excavation Work Around North Kingstown

Conventional and Advanced Systems

We install conventional septic systems and advanced treatment systems, such as nitrogen-reducing units. The soil and the state's rules decide which one fits the lot.

Residential and Commercial Work

We take on small residential repairs and large commercial site work. On new construction, we work closely with the builder and the engineer.

Priced After We Look

We look at the job before we price anything. Then the quote comes to you in writing, and the work starts once you say yes.

Google Reviews

Rated 5.0 on Google Around North Kingstown

Real reviews of our septic and excavation work, 8 reviews on Google.

Read All Reviews

South County Septic did an excellent job replacing our old septic system and leach-field. Michael surveyed the property, designed a new system, installed and worked with the RI DEM with no issues. I highly recommend this business.

Conner Marleya year ago · Google review

Michael was great! Picked up right away and was able to come within the hour to evaluate. Immediately got into motion additional resources we might need to come that day and solved the problem. Very informative and great to work with. Highly recommend.

Andrea McGregora year ago · Google review

Was referred out to Michael after an emergency waterline break that flooded our basement. He was there every step of the way and answered all the questions we had. Michael let us know what was happening during the process and could not have been happier with the outcome. Great price and great customer service! Highly recommend if anyone is in need of their services

Guides and Resources

Septic System Design Guides

Request a Quote

Get In Touch With South County Septic

Tell us what the job is and which town the property is in. Call or text (401) 474-8926 or use the form, and photos by text help.

  • Call or text (401) 474-8926
  • Serving North Kingstown, RI and the rest of Rhode Island
  • Written quotes · septic, sewer, excavation and drainage work

Request a Quote

Tell us about the septic, sewer, drainage or excavation job and where the property is. We look at the job and put the quote in writing.

Call (401) 474-8926