These trailers need cleaning right after every job, no exceptions. Skip it and the sludge sits inside the tank, hardens, and before long you are dealing with blocked pipes, bad smells and a pump that barely pulls. It is the dirty work nobody enjoys, but it is exactly what keeps the machine alive.
Get safety sorted before you touch anything. Cut the power first, then let the pressure out of the lines. Gloves, goggles and waterproof gear - wear them, every single time. Sewage is not something you want on your skin. Give the hoses and valves a quick once-over too; a cracked line will spray everything everywhere the moment you start flushing.
Then you clean the inside. Run high-pressure water through the tank and along the pipes, and keep at it until the water runs reasonably clear. Sludge sticks to the walls, so flush more than once. Pay real attention to the filter - that is where the
fine grit collects and quietly blocks things up.
The outside matters just as much. Soft brush and water to scrub the mud and grime off the body, the tyres and the pump. When you are done flushing, drain every last drop from the tank and the lines. Water left sitting will corrode the metal and turn sour in the tank.
Finish by parking it somewhere dry and well-ventilated to air out. Click each valve once or twice to make sure it moves freely, and jot down the cleaning date and condition. It takes two minutes and saves you real trouble later.
