Fats, oils and grease (often shortened to FOG) are one of the leading causes of sewer backups, and cities take them seriously. If your kitchen has a grease trap or grease interceptor, your local sewer authority almost certainly has rules about how often it's pumped, who can pump it, and what records you keep. The rules vary from city to city, but they follow the same pattern. This guide explains it, using real examples from large cities.
Grease traps vs. grease interceptors
- Grease traps are smaller units, often under a sink or in the floor inside the kitchen. They fill quickly and are usually cleaned monthly or more often.
- Grease interceptors are large tanks, usually buried outside, holding hundreds or thousands of gallons. They're typically pumped every one to three months by a licensed hauler.
Your local plumbing code and sewer authority decide which one you need, usually based on your fixtures and kitchen size.
The 25% rule
Most cities use a capacity rule rather than just a calendar. In Dallas and San Antonio, for example, cleaning is required when floating grease and settled solids together reach 25% of the total liquid depth. Some cities use a different threshold: Austin's is 50% of the wetted height.
The rule matters because a trap that's more than about a quarter full of grease and solids stops separating well. Grease starts flowing straight into the sewer, which is exactly what the trap is meant to prevent.
Pumping schedules
Many cities pair the capacity rule with a maximum interval. Houston requires every interceptor inside city limits to be fully pumped at least once every 90 days. Dallas and Austin also require pumping at least every three months, or sooner if the capacity threshold is reached. Busy kitchens often need more frequent service than the minimum.
Ask your sewer authority for your specific requirements. Many publish a one-page FOG guide for food service establishments.
Haulers and record-keeping
Grease waste can't go in a dumpster or a regular septic truck. Most cities require a registered or licensed grease hauler, and the hauler gives you a manifest (a receipt documenting how much waste was removed and where it went).
- Keep every manifest. Houston requires records to be kept on site for five years. Dallas and Austin require at least three years.
- Keep a maintenance log for any trap your staff cleans, with dates and who did it.
- Expect unannounced inspections. Several cities allow inspectors to visit without notice and ask for your records on the spot.
What the fines look like
Penalties vary widely but can add up quickly because many cities count each day as a separate violation:
| Jurisdiction | Penalty |
|---|---|
| Dallas | $200 – $2,000 per day |
| Houston | $250 – $2,000 per violation |
| Austin | Up to $2,000 per occurrence |
| Texas state level (TCEQ) | Up to $25,000 per day per violation |
Beyond fines, a restaurant whose grease causes a sewer backup can be billed for the cleanup, and repeated violations can affect permits. These are examples from Texas cities. Check your own city's ordinance for local amounts.
What pumping costs
Regularly maintained indoor grease traps typically cost $175 to $475 per cleaning. Outdoor interceptors typically cost $325 to $950 per scheduled pump-out. A neglected trap can cost up to three times as much, because it takes longer to clean and the waste is harder to remove. Stretching the schedule rarely saves money. Use the grease trap cleaning cost calculator to estimate your yearly cost.
Kitchen habits that keep you compliant
- Scrape plates and pans into the trash before they go to the dish station.
- Never pour fryer oil or grease down a drain. Store used cooking oil for a recycler. Many collect it for free and some pay for it.
- Use sink strainers to catch food solids.
- Don't use hot water or degreasers to flush grease through the trap. It just moves the grease further into the line, where it cools and hardens.
- Train new staff. Most FOG violations come from habits, not equipment.
Frequently asked questions
How often does a grease trap need to be pumped?
Indoor grease traps are usually cleaned monthly. Many cities require outdoor interceptors to be pumped at least every 90 days, or sooner once grease and solids reach 25% of the trap's depth. Check your local sewer authority's rules.
What is the 25% rule for grease traps?
Many cities require a grease trap or interceptor to be pumped once floating grease and settled solids together reach 25% of the liquid depth, because a fuller trap stops separating grease effectively.
How long do I need to keep grease trap records?
It depends on the city. Houston requires five years and Dallas and Austin at least three years. Keeping hauler manifests for at least five years is a safe habit.
Can I pump my own grease trap?
Staff can often clean small indoor traps if the city allows it and the waste is disposed of properly, but outdoor interceptors almost always require a registered or licensed hauler.
Sources: Grease Trap Locator, Texas grease trap regulations; Grease Management, grease trap pricing.