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Foundation Repair and Basement Waterproofing in Dover, NH
Dover is dye- and smoke-testing its sewers in 2026 to find roof drains and residential sump pumps tied into them, connections the city says are illegal but often made without the owner knowing. Call (978) 800-2819 or use the form. A person reads every request and replies with what happens next.
- Free for homeowners
- City and state rules on this page
- Downtown mill blocks to Bellamy Reservoir
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Basements in Dover
What's the basement problem?
Waterproofing & Drainage
Wet walls, seepage at the floor joint and spring water in the basement, handled with interior drains, exterior work or both.
Sump Pumps
New pits, replacement pumps and battery backups, with the discharge going somewhere your town allows.
Foundation Cracks & Repair
Leaking cracks, bowing or settling walls and failing mortar in old fieldstone, with an engineer brought in when the job is structural.
Crawl Spaces & Finishing
Damp crawl spaces sealed up, and dry basements turned into finished space with the right permits.
Not sure what it needs?
(978) 800-2819Tell us where the sump discharges now and when the water comes in, and we'll help you figure out what kind of job it is.
Permits
Permits and rules for basement work in Dover
Permits come from the Division of Inspection Services at 269 Mast Road (603-516-6038), open weekdays 8 to 4, and are filed on the city's permit portal (Inspection Services). The city's FAQ says "Building permits are required for any construction, enlargement, alteration, relocation, or demolition to a structure," with an exemption only for simple maintenance and repairs up to $2,500, and homeowners doing their own work need a permit too. Interior remodels need a floor plan showing "labeled rooms, appliances, egress," and new foundations are inspected "Prior to backfill." Inspections are booked on the portal or by phone, with about two business days' notice (Inspection Services FAQ).
- Inspection Services
- 269 Mast Road, 603-516-6038, weekdays 8–4
- Apply online
- permits.dover.nh.gov
- Permit exemption
- Simple maintenance and repairs up to $2,500
- Remodel plans
- Floor plan with labeled rooms, appliances and egress
- Sewer
- Sump pumps and roof drains in the sewer are illegal under city code
Fees. The newest fee schedule we could read is the FY2025 proposed schedule, written for July 1, 2024 to June 30, 2025 (FY2025 proposed schedule). City records list a newer FY2027 fee and fine schedule that we couldn't open, so ask Inspection Services for the current building permit fee rather than relying on the older figures. Under the FY2025 proposed schedule, building fees were charged by construction value, and starting work before the permit doubled them.
Codes and contractors. State law leaves permits to the city under the NH State Building Code (the IRC as adopted by NH) (RSA 155-A:2). New Hampshire moved to the 2024 codes on July 1, 2026, and through December 31, 2026 permits may be filed under either the 2021 or the 2024 codes. The Attorney General's office notes that "In New Hampshire, contractors do not need to be licensed," and advises references, proof of insurance and a written contract with scope, materials, total price and payment schedule, flagging any deposit over half the price (NH AG). Contracts over $5,000 must carry the RSA 359-G notice on resolving defects before a lawsuit (RSA 359-G). Plumbing tie-ins and new electrical circuits are licensed trades, except for an owner working on their own single-family home (Mec 300; RSA 319-C). Exterior digging needs a free Dig Safe ticket at least 72 hours ahead, not counting weekends and holidays.
Last verified November 2026. Fees, restrictions and deadlines on this page are due for re-checking by January 2027. New England Basement Pros is a referral service. We don't pull permits or do basement work; the contractor files the permit.
Water
Where the water comes from in Dover
The sewer inflow search. In a May 26, 2026 update, the city said it is continuing work to find and cut stormwater inflow and infiltration into its sewers, for federal and state compliance and to protect the Great Bay Estuary. Its engineers, Wright-Pierce, are inspecting manholes, video-recording more than 60,000 feet of sewer, and dye- and smoke-testing. Roof drains, catch basins and residential sump pumps tied into the sewer are "illegal under city code," many "are not done knowingly by the property owner," and "There are no punitive punishments"; owners may be asked to let the city inspect their roof drains (city update). The update doesn't say where sump water should go instead. State rules also keep sump pumps and foundation drains out of public sewers (Env-Wq 704), so ask the City Engineer's office (603-516-6450) before re-routing a sump line.
Rivers and flood streets. The city's 2026 Multi-Hazard Mitigation Plan Update is a draft, with its adoption dates blank (2026 draft hazard plan). It describes significant floodplain along the Cocheco River and its Blackwater, Clark and Reyners brooks, Fresh Creek, the Salmon Falls, Bellamy and Piscataqua rivers and around Bellamy Reservoir, and names these local drainage problems:
Outer Sixth Street
"Major overflows during heavy rain events," the draft plan says.
Old Colony
Two or three homes with major flooding in heavy rain and winter melt.
St. Thomas Street
Listed for aging drainage infrastructure.
Oak Street and Olive Meadow
Flooding at 75 Oak Street on September 19, 2023, and at 75 Oak Street and 6 Olive Meadow on January 10, 2024, when rain fell on frozen ground.
The draft counts 32 paid flood insurance losses totaling $921,910 and six repetitive-loss properties, two of them single-family homes. An earlier GIS analysis found about 214 parcels with structures in the floodplain, and the draft expects the 100-year floodplain to grow when maps are updated; the current county flood study dates from September 30, 2015. Look up your address on FEMA's Flood Map Service Center.
Near wetlands and tidal water. Dover zoning sets a 50-foot buffer from wetlands for most activities that change the land surface, 50 feet from streams and 100 feet from tidal waters, rivers and natural ponds; work in a wetland or buffer needs a Conditional Use Permit, and there's no citywide wetlands map (Planning FAQ). Exterior drain work near the Cocheco or the tidal Piscataqua starts with Planning.
Dover's homes
Older houses than the rest of the county
Dover's 2015 Land Use chapter, citing NH Housing Finance Authority data, found nearly 46% of the city's housing built before 1960 and nearly 29%, over 3,700 units, built before 1940, against 35% and 23% for Strafford County; 53% of units were in multi-family buildings (2015 Land Use chapter). The city says its separated sewer system dates from the 1970s (city update).
We didn't find a regulatory local historic district; Dover's Heritage Commission is advisory. In a multi-family building, the sump, the drains and the foundation are usually shared, so the owner or association is the one to call the contractor.
Radon
Radon in Strafford County basements
We didn't find a city radon figure. Strafford County is among New Hampshire's three highest counties: half of the homes tested there from 2007 to 2021 measured 7.7 pCi/L or more, and statewide about 37% of tested homes were at or above 4 pCi/L (NH DHHS data brief, August 2023). The state gives residents free test kits and says to test the lowest livable area, usually the basement (NH Radon Program). Sealing a basement is a natural time to test, and New Hampshire doesn't license mitigation contractors, so ask for national certification.
FAQ
Dover basement questions
What if my sump pump is tied into Dover's sewer?
The city counts residential sump pumps, roof drains and catch basins tied into the sewer as direct inflow that is illegal under city code. In its May 26, 2026 update on the inflow work, it said many of these connections weren't made knowingly and that "There are no punitive punishments." If you think yours is tied in, the City Engineer's office is at 603-516-6450.
Do I need a permit to finish my basement in Dover?
Yes. The city requires building permits for any construction, enlargement or alteration, exempting only simple maintenance and repairs up to $2,500, and homeowners doing their own work need one too. An interior remodel needs a floor plan showing labeled rooms, appliances and egress.
Which Dover streets flood?
The city's 2026 draft hazard plan names Outer Sixth Street for major overflows in heavy rain, Old Colony for two or three homes with major flooding in heavy rain and winter melt, and St. Thomas Street for aging drainage. It also lists flooding at 75 Oak Street and 6 Olive Meadow on January 10, 2024.
How close to a wetland can I dig in Dover?
Dover zoning sets a 50-foot buffer from wetlands for most activities that alter the land surface, and 100 feet from tidal waters, rivers and natural ponds. Development in a wetland or buffer needs a Conditional Use Permit, and the city has no citywide wetlands map, so check with Planning first.
What does it cost me to use New England Basement Pros?
Nothing. Asking is free for homeowners; the contractor prices the job, and the price and contract are between you and them.
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