The rule of thumb
Clean when the sump is 25 to 30% full or annually, whichever comes first. Florida's stormwater rules use the same threshold. A basin more than one-third full is functionally reduced and out of compliance with most ERP O&M expectations.
By property type
- HOA / residential community: annual full clean, plus a post-storm sweep after named events.
- Office park: annual, with a mid-year check on tree-canopy sections.
- Retail / big-box center: twice yearly, quarterly on restaurant pads.
- Restaurant / grocery pad: quarterly at minimum for FOG-heavy inlets.
- Industrial / warehouse: quarterly, monthly for MSGP-permitted operations.
- Automotive (body shops, dealers): quarterly with oil-water separator service.
Signals to shorten the cycle
Standing water 30+ minutes after normal rain. Sediment fanning out from a grate. Odor at an inlet (FOG or organics). Post-storm ponding that didn't exist last year. Any of those and you're due, regardless of the calendar.
What maintenance plans cost
An Annual Maintenance Plan saves 15% on every cleaning. A 3-Year plan saves 20% with the price locked for 3 years. Both include 1 visit per year, or 2 for heavy-sediment sites, and waived mobilization. Additional maintenance depends on your permit and site conditions. Compare Maintenance Plans, see catch basin cleaning cost and our full catch basin cleaning service.