Grease Trap Regulations in Idaho

Overview

Idaho has no single statewide grease trap cleaning law. Each city sets its own rules. All commercial food kitchens that discharge grease into the wastewater system must have a grease interceptor under the Idaho Department of Environmental Quality (IDEQ). Cities across Idaho enforce FOG pretreatment rules through local Public Works and utilities departments. The goal is to protect sewer infrastructure from blockages and keep water quality high.

Governing Authorities

The Idaho Department of Environmental Quality (DEQ) is a state agency. The Idaho Environmental Protection and Health Act created it. DEQ ensures clean air, water, and land in the state. It enforces state environmental rules and runs federal environmental laws, including the Clean Water Act. IDEQ runs the approved Idaho Pollutant Discharge Elimination System (IPDES) program. That program covers discharges into waters of the United States under its jurisdiction. DEQ holds the authority to run the NPDES program in Idaho.

Cities like Boise, Idaho Falls, Pocatello, and Garden City have their own ordinances. Their Public Works or Wastewater Departments hold the authority. City programs run FOG control through pretreatment divisions. Staff conduct inspections, issue permits, and confirm compliance with sizing and upkeep rules.

Key Requirements

Idaho food service kitchens must follow both state oversight and local FOG rules. Key rules include:

• Grease Interceptor Installation: All new food service kitchens that cook with fats, oils, and greases (FOGs) must have a grease trap or grease interceptor. Grease interceptors or traps must be installed and permitted before the kitchen receives a certificate of occupancy.
• Cleaning Frequency (25% Rule): A near-universal rule across Idaho cities is the 25% rule. Grease interceptors must be cleaned when combined FOG and solids reach 25% of the trap's liquid capacity. Some codes also call for cleaning when the floating grease layer passes 6 inches or settled solids pass 8 inches. The 25% rule usually means service every 1 to 3 months. The exact cadence depends on the size of your kitchen and the volume of grease it processes.
• Grease Trap Maintenance: Smaller grease traps near 3-compartment sinks must be emptied, checked, and cleaned at least once per week. Larger in-ground grease interceptors with capacities from 1,000 to 1,500 gallons may need pumping weekly, monthly, or less often. The exact cadence depends on the type of restaurant and the number of customers.
• Interceptor Sizing: Each food service kitchen must calculate grease interceptor capacity based on its size and operation type. The formula sits in the Idaho Standards for Public Works Construction 2005 (ISPWC). The minimum capacity in any one unit is 1,000 gallons, as required by Idaho plumbing code. The maximum capacity in any one unit is 1,500 gallons.
• Permits: Most food service kitchens must get a Grease Discharge Permit (GDP) or similar approval. Permit fees often depend on water usage and the kitchen's potential FOG load. A permit is needed to install a grease trap in Boise and most other Idaho cities. Check with your local city office or the Idaho DEQ for permit rules that apply to you.
• Record-Keeping: Food service kitchens must keep records of the date and time of all cleaning and upkeep for each grease trap. Records must be in a bound logbook. The book must be available for inspection by the director or designated official on demand.
• Waste Disposal: Idaho encourages recycling of used cooking oil. Owners must work with licensed waste handlers. Used oil must be recycled into products like biodiesel or disposed of under state guidance.

Fines and Enforcement

Idaho enforces FOG rules through a mix of state and local penalties. Tools vary by city. They include both civil and administrative actions.

Under Idaho's Environmental Protection and Health Act, violators can face civil penalties up to $10,000 per day per violation. DEQ generally has 60 days from the notice of violation to reach a resolution. In Pocatello, businesses or people who illegally discharge to the sanitary sewer must pay for any damages. They may be fined up to $1,000 per day per violation. They may also be charged for added monitoring and required to install upgraded equipment.

In Pocatello, an enforcement action with fines or penalties will follow the second time a kitchen is found in non-compliance. If a blockage or restriction occurs in the City sewer main, the kitchen will pay for the City's line cleaning maintenance costs.

Non-compliance can lead to fines, operational disruption, and legal action. The exact response depends on how serious the violation is. Continuous violations bring more severe consequences, up to and including business closure. Compliance helps kitchens avoid added fees, citations, and forced closure.

Some cities also charge city inspection fees. Kitchens may pay cleanup costs when FOG-related blockages in city sewer lines trace back to them.

Major City FOG Programs

Boise

The City of Boise runs a full FOG program through its Public Works Department Environmental Division. The Boise Public Works Environmental Division has guidelines for grease trap enforcement. It uses a case-by-case approach to identify violators and resolve ongoing issues. Pretreatment guidelines sit in Title 8, Chapter 14 of the Boise City Code. Boise has a busy culinary scene and strict city rules. Proper grease trap upkeep is essential for legal compliance and smooth operations. Food service kitchens must get permits, follow the 25% rule, and accept routine inspections.

Idaho Falls

Idaho Falls keeps FOG control rules through its utilities department. Every restaurant, cafeteria, or large non-residential kitchen must have a working grease removal system (GRS). Grease removal systems protect users and city pipes. They remove grease, oils, and solids before discharge. Local limits are wastewater rules that apply to commercial and industrial sites that discharge to a publicly owned treatment works (POTW). Local limits meet pretreatment program goals and the site-specific needs of the local POTW and the receiving stream. They control pollutants in wastewater discharges from those sites. For commercial kitchens that use commercial cooking equipment, grease interceptor designs must be sized to Appendix H of the Uniform Plumbing Code, or an approved equivalent design with calculations submitted.

Pocatello

Pocatello's Industrial Pretreatment Program runs full FOG rules through the Water Pollution Control division. The City requires a minimum 1,500-gallon grease interceptor and the use of Best Management Practices (BMPs) for all food service businesses. Polar FOG has no numerical limit. But discharges may not have any free-floating (visible) polar FOG entering the sewer. City Pretreatment Inspectors run routine periodic inspections. They confirm that mandatory upkeep BMPs are in place. The BMPs are fully enforceable under City Code. There is no fee to issue or renew a Waste Discharge Permit. Pocatello does charge surcharges for Total Suspended Solids (TSS), Biological Oxygen Demand (BOD), Fats, Oils & Grease (FOG), Total Phosphorus, Total Kjeldahl Nitrogen, and volume of flow.

Jerome

Jerome has detailed grease trap and interceptor rules. Cleaning and upkeep must be done when the total volume of captured grease and solids passes 20% of the unit's total volume. Each food service kitchen may contract with a grease hauler permitted by the city. Or it may write up a protocol and do its own grease trap cleaning. Jerome follows Idaho Standards for Public Works Construction (ISPWC) for interceptor design and sizing.

Frequently Asked Questions

How often do I need to clean my grease trap in Idaho?

Cleaning frequency depends on your kitchen's FOG output and trap size. Most Idaho cities follow the 25% rule. They require cleaning when FOG and solids reach 25% of trap capacity. That usually means service every 1-3 months for standard kitchens. Small under-sink grease traps may need weekly cleaning. Larger exterior interceptors in low-volume kitchens may stretch to quarterly service. Watch your trap on a regular schedule and keep detailed cleaning logs.

What happens if my facility causes a sewer blockage?

If poor grease trap upkeep leads to blockages in city sewer lines, your kitchen may be on the hook for cleanup costs. You could face fines up to $1,000 per day in cities like Pocatello. You could face up to $10,000 per day under state environmental law for serious violations. Repeat offenses can lead to mandatory equipment upgrades, more inspections, operational limits, or forced closure until you comply. Kitchens may also face public disclosure of violations.

Do I need a permit to install a grease trap in Idaho?

Yes. Most Idaho cities require permits before installing grease traps or interceptors. Permit rules vary by city. Call your local Public Works or utilities department for the application steps. Installation must follow the Idaho Plumbing Code and local ordinances. Interceptors must be sized to your kitchen's wastewater volume and FOG load. Permits usually must be in hand before occupancy certificates are issued for new sites. Some cities also require grease hauler permits for service providers.

Find Grease Trap Service in Idaho

Staying compliant with Idaho's FOG rules takes a service provider who knows state and local rules. Our directory lists 24 licensed grease trap cleaning and upkeep companies serving Idaho communities. These pros offer pumping, cleaning, inspection, and proper waste disposal. Find experienced providers in your area at https://greasetraplocator.com/us/idaho/.