Houston Grease Trap Pump-Out Requirements: The 90-Day Rule, the 25% Rule, and What Inspectors Ask For

A grease trap catches fats, oils, and grease before they leave your building. Cooking waste flows in warm. It cools inside the trap, separates, and stays put. Only the cleaner water moves on to the city sewer.

The device prevents blockages and damage to wastewater treatment facilities. That is the reason Houston writes rules around it. Grease that escapes your kitchen hardens inside public sewer lines. Enough of it, from enough kitchens, blocks the line for an entire block.

Most Houston kitchens tie the same fixtures into the trap. Dishwashers, prep sinks, mop sinks, and floor drains all drain through it.

Two types serve local kitchens:

• Small indoor units. These sit under a sink or nearby. They fill fast and need frequent service.
• Large in-ground interceptors. These sit outside, usually under the parking area or drive. They hold far more, and they need a truck.

The rules below apply either way. Size changes how often you pump. It does not change what the city expects from you.

Every interceptor inside Houston city limits must be fully evacuated at least once every 90 days. That is the outer limit the city sets. Your trap cannot go longer without an approved exception. Houston Public Works administers the program.

Fully evacuated means the whole trap. Skimming the floating grease off the top does not count. The settled solids at the bottom must come out too. A partial job leaves your trap short on working volume, and it leaves you short on compliance.

Low-volume operations have one path to a longer interval. You submit a Notice of Waiver application, and the city reviews it. The waiver only applies once approved. Until then, the 90-day clock runs.

Treat 90 days as a deadline, not a schedule. Plenty of Houston kitchens need service well before that date. The next section covers the rule that decides it for you.

The 25% rule can override your calendar. It measures how full your trap actually is, not how long since the last visit.

Wetted height is the liquid depth of the trap. It runs from the bottom of the device up to the invert of the outlet pipe. When 25 percent or more of that height holds floating material, sediment, oil, or grease, the trap needs service.

The measurement combines two layers. Grease floats and forms a cap on top. Solids sink and build sludge at the bottom. Both count toward the same 25 percent. Most operators only look at the top layer, which hides half the problem.

A clear surface does not mean a compliant trap. Sludge builds out of sight, under water that looks fine.

Track the reading at every visit. If the number climbs faster than expected, shorten your interval and stay ahead of it.

An invoice is not a manifest. A manifest is the official tracking document that follows your waste from your property to an approved disposal site. Inspectors ask for the manifest. A receipt from your vendor does not replace it.

You sign the top portion yourself. That signature states the entire contents of the trap were removed. Sign it after the work is done, not before the truck pulls in. Check the trap first, then sign.

Keep the copies onsite for five years. Both the generator copy and the returned generator copy stay at the location. Store them together where you can reach them fast.

A complete record shows:

• The date of service
• The volume removed
• The hauler's name and permit number
• The approved disposal facility
• Signatures from you and the technician

Keep a simple binder near the office, most recent on top. When an inspector asks, you should find the last service in under a minute.

If you own or manage a restaurant or food dealer establishment with a grease trap, the city treats you as a special waste generator. That status comes with its own paperwork, separate from your food dealer permit.

Your permit runs for one year from the food dealer permit issue date. Renew it every year. A lapsed permit is its own violation, even when your trap is clean.

The hauler needs a permit too. Anyone hauling special waste on City of Houston streets must hold a Transporter permit. Hiring an unpermitted truck does not shift the problem away from you. Your name is on the manifest you signed.

Ask any provider these questions before you book:

• What is your City of Houston Transporter permit number?
• Which approved facility receives the waste?
• Do you leave a signed manifest at every visit?
• Do you measure and record accumulation each time?
• Do you pump the full trap, including the settled solids?

A provider who cannot answer these on the phone will not help you during an inspection.

Start at the legal maximum, then work backward from your own readings. Ninety days is the ceiling. Your trap tells you the real number.

Three things shorten the interval:

• Trap size. Smaller units fill faster and need more visits.
• Covers per week. More plates means more grease through the same device.
• Menu. Heavy fry work and rendered fats build the cap quickly.

Watch for warning signs between visits. Drains that empty slowly, gurgling from floor drains, or odor near the kitchen floor all point to a trap that is past due.

Pumping empties the trap. It does not clear the line beyond it. Grease that already escaped hardens inside your building drain and the sewer line under the property. A freshly pumped trap sitting above a restricted line still backs up.

That part is our work. We clear and camera-inspect drain and sewer lines across the Houston metro area, so you can see what is actually happening downstream of your trap. A sewer camera inspection shows the condition of the line without guesswork.