Catch Basin Cleaning

Why South Florida basins fill faster than people expect

Sand, landscape debris, and a rainy season that arrives as intense afternoon storms rather than gentle rain. Sediment washes in fast and settles in the sump. Add a flat site with very little fall, a high water table under it, and the tidal influence coastal areas deal with, and a basin that is half full of sand simply stops keeping up. That shows up as standing water in a parking lot after every storm.

The cost of finding out during hurricane season

The wrong time to discover a blocked basin is during the first serious storm of the season. Water that cannot get into the drain goes wherever the grade sends it, which is usually toward a building. Cleaning basins before the season is ordinary maintenance. Dealing with what happens when they are full is not. The calendar here is not subtle: the work wants to happen in the spring, while the basins are dry, the crews are available and a truck can sit in a parking lot for an afternoon without anybody minding. Once the season is running, every property in three counties wants the same thing on the same week, and a basin full of sand does not care about your place in the queue.

What the sump is actually holding

Open a neglected basin on a South Florida commercial site and the profile is usually the same. Sand and fine silt at the bottom, a layer of landscape debris and mulch above it, cigarette butts and parking lot trash floating on whatever water is standing, and often a slick of oil off the pavement. All of it comes out into the tank, water included, and it all rides to an approved disposal facility under our permits. What people underestimate is how heavy saturated sand gets and how far up the sump it has crept, because from the grate you are looking at water and can only guess what is under it. Sediment depth is the number that tells you how long it has been, and it is usually longer than the file says.

Flat ground, high water and the tide

Three things make drainage here different from almost anywhere else. Sites are flat, so there is very little fall to work with and a basin set an inch high may as well not be there. The water table sits close to the surface, so a lot of structures hold standing water permanently and never really dry out, which is why sediment compacts in the sump instead of washing through. And in coastal areas the storm system is tidally influenced, so a high tide during a heavy rain means the outfall end is already full and the system has nowhere to push. None of that is fixable by cleaning, but all of it means the margin is thin, and a basin half full of sand eats the margin you have left.

Look at the structure while it is open

A basin is a concrete or block box in wet ground, and it fails from the inside where nobody sees it. Walls spall and crack. The invert, the shaped channel at the bottom that carries flow to the outlet, wears down or fills in until water sits instead of moving. Frames work loose from the surrounding pavement and grates crack or go missing entirely, which is a liability problem long before it is a drainage one. Everything above is visible in the ten minutes the structure is empty and lit, and invisible the rest of the year. So we look, we photograph, and you get told. A wall that is starting to go is a planned repair. A wall that has gone is a hole in your parking lot.

Worth knowing

Standing water that lingers after a storm, water backing up around the grate, or a smell coming off the drain are all worth a look. They rarely resolve on their own.