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KUB administers grease control requirements for Knoxville food service facilities through its Fats, Oils, and Grease program. KUB determines the type and size of grease control equipment based on the facility, the amount and type of food prepared or served, and the plumbing fixtures within the facility. Facilities with automated dishwashing equipment must install a gravity grease interceptor because hot soapy water can dissolve fats, oils, and grease, which may pass through smaller grease traps. Interceptors must be emptied at least once every three months, unless KUB gives written approval for a different schedule. Pumping records and cleaning logs from the last 24 months must be kept on site.
A grease interceptor is the least interesting piece of equipment in a restaurant and one of the few that can close it. Kitchens rarely think about the tank outside the back door until a line backs up during dinner service or an inspector asks for pumping manifests that nobody kept. Both situations are avoidable, and both are considerably cheaper to prevent than to resolve. Operators planning a build-out or taking over an existing space can start with Tennessee Standard Plumbing in Knoxville to understand what the space already has.
What follows covers who is required to have grease control equipment, how the size gets determined, how often it must be pumped, and what records have to be available when someone asks.
Grease control in the Knoxville service area falls under KUB’s Fats, Oils, and Grease program rather than a general building code provision. The program exists because fats, oils, and grease solidify in collection mains and cause sanitary sewer overflows. Requirements attach to the facility rather than to the operator, which matters when a space changes hands.
Any food service facility that will cook, prepare, or serve food is required to install and maintain properly sized grease control equipment. Coverage is not limited to new construction, and an established kitchen operating for years is no more exempt than one opening next month.
The trigger is the food service activity itself rather than seating count or square footage, so operations without a dining room are still covered. New construction and renovation both bring the requirement into play as part of the project. A restaurant moving into an existing space should check what equipment is there. They need to see if it fits the current menu. A coffee counter used different equipment than what a full kitchen needs.
This is the detail that catches operators most often. KUB will determine the type and size of the grease control equipment, and facilities should have the interceptor sized by KUB before purchasing any equipment. Buying a unit first and seeking approval afterward risks paying twice. Restaurant operators can check the restaurant plumbing services page to see what support they can expect from service providers before starting a build-out.
New construction allows the interceptor to be placed and plumbed correctly from the start, typically outside the building where a pump truck can reach it. Renovations are harder, because an existing space may lack the exterior room or the drain routing an appropriately sized unit needs. Identifying that constraint during design rather than during installation prevents a mid-project redesign.
Sizing is driven by how much grease-laden wastewater a kitchen produces and how quickly. The calculation accounts for the facility itself, the amount and type of food prepared or served, and the plumbing fixtures within the facility. Two restaurants of identical square footage can require very different equipment based on menu and equipment alone.
Fixture count and type carry substantial weight, since three-compartment sinks, wok stations, prep sinks, and floor drains all contribute flow. Menu matters as well: a fryer-heavy operation generates far more fats and oils than a salad-focused kitchen with the same seat count. Since KUB makes the decision, the best thing for an operator to do is to give correct fixture and menu details early instead of guessing.
A hydromechanical grease trap is a smaller unit, often installed under a sink or nearby, that separates grease using flow control and baffles. A gravity grease interceptor is a large exterior tank that holds wastewater long enough for separation to occur through cooling and time. Gravity interceptors typically hold 1,500 or 2,000 gallons. The larger unit costs more to install and far less to worry about.
Food service facilities with automated dishwashing equipment are required to install a gravity grease interceptor. The reason is chemical, not random: hot soapy water from a commercial dishwasher breaks down fats, oils, and grease. These then flow easily through a smaller trap while still mixed in liquid. A gravity interceptor gives the wastewater time to cool so the grease can separate out before discharge. Any kitchen planning to add a dish machine should treat that decision as a grease control decision too.
An interceptor works only while it has capacity to separate. Once accumulated grease and solids occupy too much of the tank, wastewater passes through without adequate retention time and grease enters the collection system. Pumping frequency exists to keep the unit inside its working range.
A cumulative measurement of fats, oils, and grease and food solids at or above 25 percent of the grease interceptor’s capacity is a violation. Under it, an interceptor requires servicing once the combined layers of floating fats, oils, and grease plus settled solids reach 25 percent of the interceptor’s capacity. It is a condition threshold that sits alongside the minimum schedule rather than replacing it, which means a busy kitchen can hit it well before the quarterly deadline arrives.
Before any performance threshold applies, there is a floor. Grease interceptors must be pumped out a minimum of once every three months unless otherwise specified by KUB in writing, and the maintenance must include the complete removal of all contents. A low-volume kitchen cannot simply decide a longer interval suits its accumulation rate, because the quarterly minimum applies regardless of how clean the tank looks. High-volume operations are commonly serviced monthly, and any kitchen that changes its menu, adds a fryer, or increases covers should expect to move well inside the minimum.
KUB regulations require mechanical removal, meaning the contents are pumped out and disposed of properly. Enzyme and bacterial additives marketed as reducing pumping frequency do not remove grease from the system. At best, they emulsify it so it moves further down the line, which relocates the problem into the collection main rather than solving it. Operators seeing recurring backups despite treatment products are usually looking at a capacity or scheduling issue, a pattern covered in this look at what repeated drain clogs signal.
Documentation is where otherwise compliant kitchens fail. Equipment can be correctly sized and regularly serviced, and the facility can still have a problem if the paperwork proving it is not available on site when requested.
Under KUB’s October 2024 grease interceptor standard, pumping manifests and cleaning logs covering the previous 12 months must remain on site and be produced on request. A manifest documents who pumped the unit, when, how much was removed, and where it was disposed.
Storing these only with the pumping contractor or in a manager’s email is a common and avoidable gap. A binder in the office, updated after each service, satisfies the requirement without effort. Because KUB revised these standards in October 2024, operators working from an older handout may be carrying a longer retention figure than the current document requires. The Grease Control Program confirms current requirements at 865-594-8337 or greasecontrolprogram@kub.org.
Ongoing problems are small equipment left by the last tenant, settings that were made when installed and not updated as usage increased, missing records for part of the retention time, and depending on additives instead of regular pumping. Kitchens that added a dish machine after opening without revisiting grease control are another frequent case, since that single change can shift the requirement toward a gravity interceptor.
The direct consequences are enforcement actions and the cost of correcting undersized or neglected equipment. The indirect effects are often bigger: a grease backup during service can stop income, may require a shutdown while it is cleared, and causes a cleanliness problem in a regulated area. Facility teams managing several locations can standardize the interval and the record format across sites to remove most of this risk.
Grease control becomes routine once the equipment is right and the schedule matches actual volume. Our team at Tennessee Standard Plumbing works with restaurant operators and property managers throughout Knoxville and Knox County, and we are glad to look at an existing setup before it becomes an emergency.
Four points are worth carrying into any build-out or takeover. KUB sizes the equipment, so involve them before purchasing. Automated dishwashing pushes a facility toward a gravity interceptor. Pump at least once every three months unless KUB approves otherwise in writing, and sooner when the 25 percent threshold is reached. Keep the previous 12 months of service manifests on site.
Restaurant operators and facility managers can reach our team at (865) 352-9003 or contact our team online. Peaceful Pipes, Peaceful Life.
We serve Knoxville, Maryville, Oak Ridge, and communities across Knox County and East Tennessee.
KUB does. It decides the kind and size of grease control equipment based on the facility, the type and amount of food cooked or served, and the plumbing fixtures there. Facilities should have the interceptor sized by KUB before purchasing any equipment.
Any commercial facility that cooks, prepares, or serves food must install and maintain properly sized equipment. Coverage is not limited to new construction, so an established kitchen is no more exempt than one opening next month. The requirement attaches to the food service activity rather than to seating count, so operations without a dining room are still covered.
Hot soapy water from automated dishwashing dissolves fats, oils, and grease, which then pass through a smaller trap while still in solution. A gravity interceptor holds the wastewater long enough for it to cool so the grease separates before discharge. Facilities with automated dishwashing are required to install one.
Gravity grease interceptors commonly hold 1,500 or 2,000 gallons. They are installed outside the building where a pump truck can reach them. The exact size for a given facility is determined by KUB rather than selected from a catalog by the operator or the equipment vendor.
It is a performance standard used in Tennessee, including by KUB, under which an interceptor requires servicing once the combined layers of floating fats, oils, and grease plus settled solids reach 25 percent of the interceptor’s capacity. It works alongside the quarterly minimum rather than replacing it, so a busy kitchen commonly hits it first.
At least once every three months, unless KUB approves a different schedule in writing. That quarterly minimum applies regardless of how slowly a kitchen accumulates grease. High-volume operations are commonly pumped monthly because they reach the 25 percent capacity threshold well before the quarterly deadline arrives.
No. KUB regulations require mechanical removal, meaning the contents are pumped and disposed of properly. Additives do not remove grease from the system, and emulsifying it simply moves it further into the collection main. Recurring backups despite additive use usually indicate a capacity or scheduling problem.
Pumping manifests and cleaning logs covering the previous 12 months, under KUB’s October 2024 grease interceptor standard. A manifest records who performed the service, the date, the volume removed, and the disposal destination. Operators working from an older KUB handout may be carrying a longer retention figure than the current standard requires.
The existing equipment should be verified against the incoming menu and fixture plan rather than assumed adequate. A previous tenant with a limited menu may have equipment sized for far less grease load. Renovation also triggers the installation and maintenance requirement for grease control equipment.
Fats, oils, and grease solidify inside collection mains and cause sanitary sewer overflows affecting the wider system. That is why the program exists and why enforcement is active. For the individual facility, the immediate stakes are service interruption, closure risk during a backup, and correction costs.
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