There are two rules, not one. The 90 day baseline is the one everybody quotes; the 25 percent fill threshold is the one that actually decides most kitchens. Here is how to work out which governs yours.
Whichever comes first: 90 days, or the point at which accumulated fats, oils, grease and settled solids reach 25 percent of the total liquid depth of the device.
Nearly every compliance problem we encounter in Cape Coral comes from operators knowing the first half of that sentence and not the second. Quarterly service gets scheduled, the invoices accumulate, and the kitchen backs up anyway, because the tank was crossing 25 percent at week six every single cycle.
Total liquid depth: water surface down to the tank floor. Grease cap: thickness of the floating layer. Solids: depth of settled sludge on the bottom.
(grease cap + solids) divided by total liquid depth. Over 0.25, the device is due. Do this once a fortnight for two months and you will know your real fill rate better than any scheduling assumption.
A grease interception device works by residence time. Wastewater enters, slows down, and stays in the tank long enough for fats and oils to rise and solids to settle, so that what leaves through the outlet tee is the relatively clean middle layer.
Everything occupying the tank that is not that middle layer reduces the working volume. At 25 percent accumulation the remaining residence time is at the edge of what reliably produces separation. Past that, flow velocity through the tank rises, the middle layer gets thinner, and grease begins carrying through into the outlet line rather than being retained.
The important consequence is that separation does not fail suddenly at some visible point. It degrades. A device at 40 percent is still doing something, just not enough, which is why the symptoms creep in over weeks rather than announcing themselves.
These are working starting points based on what we find in Cape Coral tanks, not regulatory categories. Verify against your own measurements.
| Kitchen Type | Starting Interval | Why |
|---|---|---|
| Fried seafood, fried chicken, heavy fryer banks | 30 days | The highest grease load per cover of any kitchen type. Small and mid-size traps in these operations routinely cross 25 percent inside a month. |
| Full-service restaurant with grill and fryer | 45 to 60 days | The most common Cape Coral profile. Quarterly is usually too slow, particularly on an under-sink unit and particularly in season. |
| Pizzeria, bar kitchen, cafe with flat-top | 60 days | Moderate load, but cheese fats and grill drippings accumulate faster than operators expect. |
| Bakery, sandwich shop, coffee with light food | 60 to 90 days | Genuinely lower load. These are the kitchens where the 90 day baseline is realistic rather than aspirational. |
| Correctly sized outdoor interceptor, moderate volume | 90 days | Large buffer volume means the calendar usually bites before the fill threshold does. Verify rather than assume. |
| Undersized tank on a changed-use tenancy | 30 days or less | The tank was sized for the previous business. Fix the tank if you can, because monthly service is a permanent tax on a sizing error. |
A hundred-seat pizzeria and a hundred-seat fried seafood house produce completely different grease loads. Fryer volume, grill drippings and the amount of animal fat going down the sink matter far more than covers.
The most common structural cause, and usually inherited. A tenancy changed use, the kitchen got heavier, and the tank stayed the same. A permanently monthly interval on a small trap is almost always a sizing problem wearing a scheduling costume.
Fixtures that should not be on the grease line, and fixtures that should be but are not, both distort the picture. Worth confirming during any remodel.
In Cape Coral this is not a minor adjustment. Covers rising sharply from roughly December through April change the fill rate materially, and a fixed year-round schedule set from summer volume will be wrong for the months that matter most.
A tank that has been skimmed rather than evacuated never regains full working volume, so it reaches 25 percent progressively faster each cycle. If your interval seems to be shortening year over year with no change in business, this is usually why.
Start with a full evacuation so you have a clean baseline. Measure at the midpoint of your proposed interval. If accumulation is already near 25 percent at the halfway mark, the interval is too long. If it is under 10 percent at the scheduled date, you may have room to extend, up to the 90 day ceiling and no further.
Two cycles of that gives you a defensible, evidence-based schedule, which is worth something beyond the operational benefit. An inspector asking why you service at 45 days gets a much better answer from "we measured" than from "that is what the contract said".
The service interval and fill threshold sit in Florida's plumbing code and are reinforced by local sewer-use ordinances. The separate question of who may transport grease waste and where it may be delivered is handled at state level, with the Florida Department of Environmental Protection administering the relevant programme and the Florida Department of Health overseeing hauler permitting.
Our Lee County regulations guide covers the compliance picture in more detail, including manifests and record retention. If you would rather someone else tracked the interval for you, that is what route pumping is for, and coverage is listed on the service area page.
A maximum. It is the longest you may go between services, not the interval you should be aiming for. Treating it as a target is how kitchens end up compliant on paper and backed up in reality, because the second rule, the 25 percent fill threshold, frequently arrives well before day 90.
Measure the total liquid depth from the water surface to the tank floor. Then measure the thickness of the floating grease cap and the depth of the settled solids on the bottom, and add them together. If that combined figure exceeds a quarter of the total liquid depth, the device is due. A clean dipstick and a torch at the end of a shift will do it.
Not as a routine schedule. The 90 day figure is the statutory ceiling in Florida's plumbing code and it is not something a service company can waive for your convenience. Any contractor offering you a six-month routine interval on an operating commercial kitchen is offering something they are not in a position to offer.
Very possibly. A device that reaches 25 percent in a month is either badly undersized for the fixture load and cooking type, or is taking flow from fixtures that should not be on the grease line. Both are worth investigating, because the alternative is paying for twelve services a year to compensate for a tank that should have been larger.
In Cape Coral, significantly. A restaurant whose covers double from roughly December through April is not the same kitchen in February that it was in September, and a fixed year-round interval set from off-season volume will be wrong for the busiest months. Tightening for the season and relaxing afterwards is cheaper than twelve monthly services and far cheaper than an in-season failure.
Tell us your trap size and what you cook. We will suggest a starting interval, then confirm it against what we actually find in the tank over the first two visits rather than guessing once and billing forever.
Prefer to write it out? Use the contact page and we will come back to you with a number.