✓ NH Licensed Septic Installer Serving Southwestern & Central NH

Septic failed? Drainage problems? Building a new home?

Whatever your land is throwing at you, we've dug through it before. Straight answers, a written estimate, and work done right the first time.

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Pipe trench excavation on a Granite State Site Services job site

What we solve

Sound familiar? We can help.

Septic failed?

Licensed installation of replacement septic systems — soil testing, state approval, and the dig, handled start to finish.

Need a new septic system?

We install systems for new construction and work hand-in-hand with several licensed septic designers to keep your build on schedule.

Drainage problems?

Wet basements, standing water, washouts — Marc will walk your property with a free site survey, then regrade, install drains, and move water where it belongs.

Building a new home?

Complete site work: clearing, foundation dig, utilities, backfill, and finish grading — plus quality well drillers we trust to get your water right.

Need a driveway?

New driveways built to last, plus regrading and repair of ones that haven't.

Ledge in the way?

A hydraulic hammer attachment breaks up rock and shelf — no blasting contractor needed for most jobs.

Near water or wetlands?

Marc works with Shoreland and wetland specialists to obtain the permits and approvals your project needs.

Need fill or gravel delivered?

Fill, gravel, stone, and loam delivered — and spread, if you'd like.

Recent work

Real jobs, photographed start to finish.

Every project photographed, start to finish. Ask us for references — our customers are our best advertising.

House lot — clearing & ledge removal

Culvert & road work — compaction

Marc Longval

Owner & Operator

When you call, you talk to Marc — the same person who shows up with the machine. No sales staff, no runaround. A licensed septic installer with more than 25 years of experience across septic, excavation, drainage, and site work — and the equipment to handle your project from soil test to final grade.

We work with homeowners and builders across the region — alongside several licensed septic designers, engineers, quality well drillers, and shoreland and wetland specialists for permits and approvals. One call brings the whole team.

Service area

Based in Washington, NH

Washington sits in the hills of western New Hampshire, just south of Lake Sunapee. We travel up to about 90 minutes in any direction — north to Lebanon and the Upper Valley, east through Concord, south through the Monadnock region, and west to Brattleboro, VT. If you're anywhere in western or central New Hampshire — or just across the river in Vermont — we'll come to you.

WashingtonHillsboroughSunapeeNew LondonBradfordAndoverNewportClaremontLebanonKeenePeterboroughConcordBrattleboro, VTWest Windsor, VT

Request a free estimate

Tell us what's going on with your property. We'll get back to you within one business day.