By SemperScreen®. We own residential and commercial real estate properties across the United States, and we built the permanent sink screen for our own buildings before we sold it to anyone else.
Grease interceptor pumping is usually budgeted as a fixed recurring cost. It is not fixed. Under the 25 percent rule that most FOG programs run on, your required frequency is a performance standard measuring combined grease and settled solids against the interceptor's operating depth. Solids are half of that measurement, and they are the half you can change upstream.
What actually sets your pump-out frequency?
Two numbers, and only one of them is under your control.
The ordinance ceiling. Most FOG programs set a hard maximum interval regardless of fill level. Phoenix requires gravity interceptors at food service establishments to be fully pumped at least every three months, hydromechanical interceptors at least every 30 days, and no hydromechanical interceptor to go beyond 90 days without maintenance.1 Ninety days is a common ceiling nationally. You cannot get below the ceiling by being clean.
The 25 percent rule. Between today's frequency and that ceiling is where the money is. Portland's sewer authority sets cleaning frequency by establishment type, interceptor size and flow volume, and states that most interceptors need cleaning when they become 25 percent full of FOG and solids.2 Phoenix words it as combined grease, lint, oil, sand, sludge and solids not exceeding 25 percent of total liquid volume capacity at the static water level.1 Tacoma requires cleaning whenever 25 percent of any chamber fills with FOG or solids.3
The industry description of what that rule is doing is the important part: it is a performance-based standard that lets maintenance schedules reflect actual usage.4 Performance-based means the schedule follows the load. Change the load and the schedule follows.
On the permission question. Nothing here permits reducing or bypassing the interceptor, and you should not read it that way. Codes push in the opposite direction: under the International Plumbing Code, where a food waste grinder connects to a grease interceptor, a solids interceptor must separate the discharge first, with both devices sized for the grinder.5 Some jurisdictions bar the connection outright, which we covered in commercial garbage disposal bans. What is permitted, and in fact encouraged by every program we reviewed, is reducing what reaches the device in the first place.
SemperScreen® recommends that you always refer to local building codes when modifying a building's plumbing system.
Why solids matter as much as grease
Because the rule measures both, and most prevention effort only addresses one.
Grease is the headline. The U.S. Environmental Protection Agency's report to Congress found grease from restaurants, homes and industrial sources to be the most common cause, at 47 percent, of reported sewer blockages, and federal pretreatment regulations at 40 CFR 403.5(b)(3) prohibit discharging solid or viscous pollutants in amounts that will cause obstruction.6 Note the wording of that federal prohibition. It says solid, not just greasy.
Inside the interceptor, solids do three things.
They occupy the 25 percent. Settled solids in the bottom chamber count toward the threshold exactly as floating FOG does.1,2 Every gallon of food that settles is a gallon of headroom you no longer have.
They make the service more expensive. Traps serviced at or below the 25 percent threshold are faster and less expensive to clean; those allowed to exceed it hold more waste volume, denser accumulated FOG, and potentially compacted solids requiring additional extraction effort.7 Disposal cost scales with volume and is a significant component of the price.7
They cannot be skimmed away. Auburn's ordinance is explicit that maintenance means removing all FOG, solids and water, and that skimming the surface layer or any partial cleaning does not constitute maintenance.8 Solids at the bottom are the reason a full pump-out is required rather than a skim.
And what does not work is worth stating plainly, because vendors still sell it. Portland's guidance is that chemical emulsifiers, solvents and caustics do not eliminate FOG but move the problem down the line, and that enzyme-treated FOG released to sewer lines can re-form into solid matter and obstruct pipes.2 Some programs disqualify establishments using additives from sewer rate reductions entirely.2
What to establish before changing anything
Four things, and none of them requires a consultant.
Your ordinance ceiling and your current interval. If you are already at the ceiling, upstream changes will not reduce frequency, though they will still reduce service cost and the risk of an exceedance finding. If you are pumping more often than the ceiling, the gap is your opportunity.
Which fixtures actually reach the interceptor. Break room and pantry sinks are routinely assumed to sit outside the FOG program because the room is not a commercial kitchen. Sometimes that is right. Sometimes the fixture is on a branch that reaches the interceptor anyway. This is a drawing question.
What the last few manifests say. Your hauler documents what came out. Pattern across services tells you whether you are grease-loaded, solids-loaded, or both, and it costs nothing to read.
Whether a disposer is feeding it. If there is one, it is manufacturing the exact load the interceptor was not designed to receive, and it may not be permitted on that branch at all.5
One structural note. Several programs require food service staff to inspect and clean grease traps on a weekly basis until logged data justifies a lower frequency.9 If that applies to you, the log is the mechanism by which reduced loading turns into a reduced schedule. Keep it properly and it becomes your evidence.
Where this applies beyond restaurant kitchens
FOG programs cover more building types than operators expect. Tacoma's guidance lists restaurants, cafes, catering facilities, commissaries, hotels, cafeterias, convenience stores, full-service grocery stores, schools, hospitals and food manufacturing plants as needing grease protection.3
Healthcare. Nutrition services and cafeteria kitchens are conventional FOG-program fixtures. The ones that get missed are unit pantries, nourishment rooms and staff break rooms, which are numerous, lightly supervised, and rarely in anyone's FOG plan even when they discharge to the same system.
Hospitality and senior living. Banquet pantries, floor galleys and pantry sinks behave the same way: low individual volume, high fixture count, no single person who owns the sink. Aggregate load through them is not small.
In both cases the fixture-level answer is the same and the operational answer is the same. What differs is only how many of them you have.
The options
Solids interceptor upstream. Where the IPC governs and a grinder is present, this is required rather than optional, and it works.5 It is also another serviced device on another schedule.
Remove the disposer. Addresses the source rather than the symptom, and in several jurisdictions is what the code already requires.
Removable covers at each sink. They meet the fixture requirement and they work while they are in the sink. In a commercial building, that is the problem. A cover in a shared room belongs to nobody, gets lifted out to drain a container, set on the counter, and thrown out with the scraps. In a hospital pantry or a hotel galley with dozens of such fixtures, the failure is not one sink; it is an unknown fraction of them at any given time, and you have no way to know which.
A permanent screen at each sink. Same fixture compliance, nothing to remove, and the load reduction is continuous rather than occasional. In fact, three municipalities have implemented such a change into code: Solana Beach, CA per Ord. 328, 200411; El Cajon, CA per Ord. 4930 §10, 200912; and Richmond, CA per Ord. No. 18-11 N.S., §I, 201113, all explicitly cite, "Any fixture connected to a grease interceptor shall have a nonremovable, secured food strainer of such integrity to withstand daily operational usage."
Additives. Covered above. The programs themselves say these do not work.2
Doesn't screening at the sink just move the problem to the screen?
Yes, and that is the point. The question is where you would rather handle it.
Food in a screen is visible, reasonably dry, at waist height, and goes into a bin in a second or two. Food in an interceptor is submerged, mixed with FOG, measured against a regulatory threshold, and removed by a vacuum truck you pay by volume. Those are the same solids in two places, and the cost difference between the two places is the entire argument.
Clearing is a point-of-use task. Whoever used the sink moves the scraps into the bin with a paper towel or a hand. Janitorial cleans the screen further on the daily round, in the same pass that empties the bins. Neither is a work order.
Be clear about the limit, though. A screen stops food solids. It does not stop liquid grease poured down a drain, and grease is the larger half of what the 25 percent rule measures. This changes the solids side of the equation and it does not replace grease handling, staff training, or the interceptor itself. Anyone telling you otherwise is selling something.
What it costs, and what changes
Scheduled service for a small indoor trap typically runs $125 to $180, and a standard 1,000-gallon outdoor interceptor on contract runs $225 to $450.7 Across the market, commercial cleaning ranges from about $115 to $1,500 or more per service depending on size, condition and access,7 with one hauler putting the practical range at $115 for a small high-frequency indoor trap up to about $1,040 for the largest tanks.10 Hydro-jetting adds $300 to $600 when it is needed.7
Three levers, in order of size.
Frequency. At $150 to $200 per monthly service, a small indoor trap costs $1,800 to $2,400 a year.7 Moving from monthly toward the ordinance ceiling is the largest available saving, and it is only available if the 25 percent measurement supports it.
Per-service cost. You pay by volume and by density. Solids kept out are volume nobody extracts, hauls, manifests or disposes of.7
Neglect avoidance. A trap that has not been pumped in over six months, with solidified buildup, can cost two to three times the standard rate.7 Slower loading buys margin against that outcome.
The fourth cost is the one that does not appear on the FOG line at all. In published SemperScreen® collateral we anchor a plumbing service call at $250+ per call, and the branch lines feeding an interceptor generate those independently of the interceptor's schedule.
What to install
The decision at each fixture reduces to one question: does this control stay in place without anyone deciding to leave it there?
The SemperScreen® permanent sink screen is the only non-removable permanent sink screen on the market, which is why it belongs in a multi-fixture commercial environment rather than a resident welcome packet. It is Type 304 stainless steel with a polished finish and a brushed trim ring, one pound, fitting standard three and a half inch drains with a custom tube nut on the one and a half inch tailpiece for more thread contact. Its proprietary double-walled technology gives it a perforation surface area exceeding that of the connecting pipe, so it does not restrict the drainage path. It has been tested and COMPLIED with ASME A112.18.2-2020 / CSA B125.2-20, with the detail on our certifications and testing page.
Installation is a retrofit at about fifteen minutes per drain with no plumbing modifications, which matters when the scope is forty pantry sinks rather than one. More than 20,000+ sold since 2017, with a 5-year commercial warranty on commercial installations.
The multi-site version of this is already running:
"I really appreciate what your product has done for the sites it is installed in—it's impressive work." Master Plumber, Major Retailer with 1,900+ stores
The sequence we would suggest: read your last four manifests, confirm your ordinance ceiling, fix the fixture-level input, then apply for the frequency review your program allows once the logs support it. Doing the last step first is how facility teams get told no.
For rental and property teams: We know you have at least one drain that keeps clogging (we have experience with those). Contact us and let's discuss testing our permanent sink screens in those bad drains.
Commercial properties (restaurants, hotels, retail breakrooms, hospitals, senior care facilities, office breakrooms, industrial warehouses) have some of the same issues with food waste. Find out what we recommend in these larger facilities.
To calculate a portfolio ROI see integrated facilities management page, and to source through your supply house use Find a SemperScreen® Dealer.
Frequently asked questions
What is the 25 percent rule for grease interceptors? Most FOG programs require an interceptor to be pumped before combined floating FOG and settled solids reach 25 percent of its operating depth or liquid volume.1,2,3 It is a performance standard rather than a fixed calendar, so the schedule follows the actual load.4
Can reducing solids lower my required pumping frequency? It can, up to your ordinance's maximum interval, which you cannot go beyond regardless of fill level.1 Where a program sets frequency from logged inspection data, the log is the mechanism.9
Do grease trap additives reduce pumping frequency? Sewer authorities say no. Chemical emulsifiers move FOG downstream rather than eliminating it, and enzyme-treated FOG can re-form into solid matter in the sewer.2 Some programs disqualify users of additives from rate reductions.2
Does a break room sink discharge to the grease interceptor? It depends on how the fixture is piped, not on what the room is called. Confirm from the drawings and with your sewer authority.
Will a sink screen stop grease? No. It stops food solids, which are one half of what the 25 percent rule measures. Grease handling, staff practice and the interceptor itself all remain necessary.
References
- "28-15 Interceptors — Maintenance." Phoenix City Code. Retrieved from https://phoenix.municipal.codes/CC/28-15
- "Grease Interceptors and How to Maintain Them." City of Portland Bureau of Environmental Services. Retrieved from https://www.portland.gov/bes/preventing-pollution/fats-oil-and-grease/grease-interceptors
- "Grease Interceptor Sizing and Installation Guidelines." City of Tacoma, Planning and Development Services. 2025. Retrieved from https://www.tacomapermits.org/tip-sheet-index/grease-interceptors
- "How to Build an Effective Municipal FOG Ordinance." United States FOG Alliance. 2026. Retrieved from https://usfoga.com/municipal-fog-ordinance-essential-components/
- "Section 1003 Interceptors and Separators," 1003.3.2 Food waste grinders. International Plumbing Code, as published by the City of Wildwood, Florida. Retrieved from https://www.wildwood-fl.gov/waste-water/page/section-1003-interceptors-and-separators
- "Controlling Fats, Oils, and Grease Discharges from Food Service Establishments." U.S. Environmental Protection Agency, National Pretreatment Program, EPA-833-F-12-003. 2012. Retrieved from https://www.epa.gov/sites/default/files/2020-02/documents/pretreatment_foodservice_fs1.pdf
- "How Much Does Grease Trap Cleaning Cost? 2026 Pricing Guide." Grease Trap Locator. 2026. Retrieved from https://greasetraplocator.com/grease-trap-cleaning-cost/
- "13.22.070 Grease traps and grease interceptors — Cleaning and maintenance." Auburn City Code. Retrieved from https://auburn.municipal.codes/ACC/13.22.070
- "Fats, Oil and Grease (FOG) Best Management Practices Manual." York County, South Carolina. 2022. Retrieved from https://www.yorkcountysc.gov/DocumentCenter/View/6687/FOG-Program-Manual-And-Application-2022
- "Grease Trap Pumping Cost." Grease Cycle. 2025. Retrieved from https://grease-cycle.com/grease-trap-pumping-cost/
- §6.32.100.I Grease control devices – Maintenance. Solana Beach, CA City Code. Retrieved from https://www.codepublishing.com/CA/SolanaBeach/html/SolanaBeach06/SolanaBeach0632.html
- §13.38.050C.9 Grease interceptor design and maintenance requirements – Interceptor Maintenance. El Cajon, CA City Code. Retrieved from https://ecode360.com/44371816
- §12.18.030.2.C.7 Grease Interceptor Maintenance Procedures and Program. Richmond, CA City Code. Retrieved from https://www.ci.richmond.ca.us/DocumentCenter/View/7844/1218-All
