# Grease trap pump-out interval estimator

Estimate an interval from measured accumulation after a complete clean. Austin uses wetted height; Toronto and Portland use the basis in their guidance. Confirm the device and measurement with a qualified contractor. Starting values are examples, not measurements of your device.

Use the tool on the [web page](https://greasecleaning.fyi/tools/grease-trap-pump-out-estimator). It works without JavaScript.

## How to use it

1. Choose local example and device.
2. Enter days since the last complete clean.
3. Enter combined grease and solids measured.
4. Read the result.

## How it works

The calculation divides elapsed days by measured accumulation and multiplies by the local threshold, rounded down. This assumes a constant accumulation rate after a complete clean. Real loading changes. It cannot authorize a longer interval.

Austin Water: pump at least every 90 days or sooner at 50% combined grease and solids of wetted height. Source: https://www.austintexas.gov/department/grease-trap-maintenance . Fetched 2026-11-10.

Toronto Water: hydromechanical interceptors every four weeks (28 days), before 25% combined grease and solids by liquid volume, or before rated grease capacity is exceeded, whichever comes first, unless the City permits a different frequency. This tool does not calculate rated capacity. Source: https://www.toronto.ca/services-payments/water-environment/water-sewer-related-permits-and-bylaws/sewers-by-law/mandatory-grease-traps-for-food-service-establishments/environmental-code-of-practice/grease-interceptor-maintenance/ . Fetched 2026-11-10.

Portland: most interceptors need cleaning at 25% combined FOG and solids. The City sets cleaning frequency; some high-efficiency devices have different thresholds. This tool excludes those exceptions and does not know the City-assigned interval. Use the earlier local deadline. Source: https://www.portland.gov/bes/preventing-pollution/fats-oil-and-grease/grease-interceptors . Fetched 2026-11-10.

These examples do not cover other cities, gravity interceptors in Toronto, or a device with a specific permit condition. Do not enter a tank or open heavy covers to obtain a reading.

> Estimate only. No legal or engineering advice. Confirm device type, measurement basis, rated capacity and local requirements. Backups and defects need qualified attention regardless of this estimate.

## Questions

### Can this extend the local pumping deadline?

No. Use the earlier local deadline and condition trigger. Obtain authority approval for any exception.

### Why do measurement units matter?

Wetted height and liquid volume are different bases. A depth percentage cannot automatically be used as a volume percentage.