How do I properly clean a grease trap?

Protect the Tuolumne River by keeping grease out of sewers. These are the steps to properly clean a grease trap:

Scoop top 

Open cooled trap. Remove surface grease solids with slotted spoon, and oil with solid spoon. Place in a double lined plastic bag.

Scrape sides

Scrape grease from sides and dividers into the disposal bag.

Check solids

If sediment is more than two (2) inches thick, call a licensed company to pump the trap clean.

Check Screen

Remove, inspect, and clean screen.


Pour cat litter into bag of grease and mix until solidified.


Tie bag securely and place in dumpster.

Reassemble, refill, record

Reassemble, tighten lid, and record on log sheet.

For assistance, call the City of Modesto Environmental Services at (209) 577-6200. View this information with photos in a printable PDF.

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1. Are personal hygiene wipes labeled flushable actually flushable?
2. How do I properly clean a grease trap?