Grease Trap Regulations in New Hampshire

Overview

New Hampshire food service kitchens work under a two-layer set of fats, oils, and grease (FOG) rules. The NH Department of Environmental Services (NHDES) requires all commercial food kitchens to maintain their grease traps under municipal and state guidance. City sewer utilities enforce local pretreatment rules that work alongside the state rules. Together they prevent sewer blockages and protect water quality.

Governing Authorities

RSA 485-A (Water Pollution and Waste Disposal) is the state law on sewage and waste disposal in New Hampshire. Operating standards for grease interceptors sit in the NHDES Env-Wq 1000 series administrative rules, mainly Env-Wq 1010 and Env-Wq 1012. The New Hampshire Department of Environmental Services (NHDES) runs state-level rules through its Subsurface Systems Bureau and Wastewater Engineering Bureau. Those bureaus set minimum standards for grease interceptor design and upkeep.

At the city level, most enforcement runs through local water and sewer utilities. The City of Concord has Ordinances and Regulations that require a Grease Removal Device (GRD) for any kitchen serving food or drink. The goal is to keep FOG out of the sewer collection system. Manchester Water Works, Nashua Division of Public Works, Portsmouth Public Works, and other city authorities run pretreatment programs with their own permit, inspection, and recordkeeping rules.

Key Requirements

Commercial sites and dwellings where food handling and prep happen must have a gravity grease interceptor. It must be sized for at least 36 hours of hydraulic detention and a minimum volume of 1,000 gallons. These rules apply to kitchens that use individual sewage disposal systems instead of city sewer connections.

Key compliance rules include:

• Interceptor Installation: Food service kitchens must install properly sized grease removal devices (grease traps or interceptors). Size depends on the type of kitchen and its wastewater volume.
• Cleaning Frequency: Follow the 25% rule. Devices must be cleaned before FOG and solids pass 25% of total capacity. Typical intervals run from weekly to quarterly. The exact schedule depends on trap size and use.
• Licensed Haulers: Grease may be removed from a gravity grease interceptor only by a licensed septage hauling vehicle.
• Record Retention: Keep upkeep logs, service receipts, and waste manifests for at least three years.
• Best Management Practices: Kitchens must use BMPs such as dry-wiping cookware, installing sink strainers, disposing of oil properly, and training staff.

Fines and Enforcement

Failing to comply can lead to citations, fines, or, in serious cases, closure orders. Specific fine amounts vary by city. State enforcement focuses on septic system violations. City programs apply direct penalties for FOG violations.

Enforcement tools include:

• Routine inspections by city FOG inspectors and health departments
• Notices of violation with set deadlines for repair
• Administrative fines for breaking permit conditions
• Cost recovery for sewer system blockages and emergency cleanups caused by FOG
• Permit suspension or revocation for repeat violations
• Mandatory installation of properly sized exterior grease interceptors for kitchens that cause system problems

Kitchens that cause sewer blockages from FOG face direct fines and liability for cleanup and repair costs. City authorities can also require compliance plans and upgraded pretreatment equipment as a condition of staying open.

Major City FOG Programs

Manchester

Manchester Water Works runs a structured FOG control program. It requires grease control devices for all food service kitchens. Owners must keep proper records of grease trap and interceptor cleanings. Records get uploaded to the city's compliance database. The program puts the focus on preventive upkeep and routine inspections to protect the city sewer system.

Concord

The City of Concord has Ordinances and Regulations that require a Grease Removal Device (GRD) for any kitchen serving food or drink. Food Service Establishments must have a GRD, such as an internal grease trap or external grease interceptor. For more details, kitchen operators can call the City's Code Administration Department at 603-225-8580. About 5% of sewer blockages in Concord come from FOG that is not managed properly.

Nashua

Nashua Division of Public Works enforces FOG pretreatment rules for all commercial food kitchens. The program requires grease interceptor installation, routine upkeep by licensed haulers, and three-year retention of service manifests. Nashua inspectors run routine site visits to confirm kitchens follow grease control rules and cleaning schedules.

Portsmouth

The City of Portsmouth times its Fats, Oils and Grease (FOG) 2023 Permit application process to match the Health Department's Food Permit Renewal Campaign. The program covers all food service kitchens that operate grease traps or interceptors. The FOG permit application fee is $75 for existing kitchens. Starting in September 2024, when food service kitchens renew their permits, they must show written proof (a log or receipts) of their required grease trap or interceptor cleanings.

Frequently Asked Questions

How often must I clean my grease trap or interceptor?

Cleaning frequency depends on device size and FOG output. The industry standard is the 25% rule: clean the device when FOG and solids reach 25% of total capacity. Small under-sink grease traps may need weekly cleaning. Larger exterior interceptors usually need service every one to three months. Watch fill levels and adjust your schedule so the device never passes 25% capacity.

Do I need a grease trap if I only serve coffee and baked goods?

Rules vary by city and the specifics of your kitchen. Sites with little cooking, like bakeries, coffee shops, and delis without fryers or grills, may use smaller grease traps. In some cases they may get waivers. But any kitchen with three-compartment sinks or dishwashing usually needs some form of grease removal device. Call your local water/sewer department and NHDES to confirm the rules for your kitchen type.

What records must I keep for FOG compliance?

New Hampshire cities require food service kitchens to keep full cleaning and upkeep records for at least three years. Required paperwork includes service receipts from licensed septage haulers, upkeep logs with dates and waste volume, transport manifests, and inspection reports. Many cities now require digital submission through online portals. Keep all paperwork easy to find for city inspectors and health department staff.

Find Grease Trap Service in New Hampshire

We list 23 licensed grease trap service providers across New Hampshire. These pros offer cleaning, upkeep, and compliance paperwork for food service kitchens statewide. Find licensed septage haulers, grease interceptor installers, and upkeep contractors who know NHDES rules and local city FOG programs. Visit our New Hampshire grease trap service directory to start.