Guide
Concrete pump washout: whose problem is it, and where does it go?
Updated
Washout is the end of the job that gets agreed at the start, or argued about in the dark. It is also the part with genuine environmental consequences.
Why washwater is not just dirty water
Water that has been in contact with fresh concrete or cement is highly alkaline. Discharged into a surface water drain, a ditch or a watercourse it is damaging to aquatic life, and pollution of controlled waters is an offence, not a tidiness issue. Surface water drains generally run to a watercourse, not to treatment, so the rule on site is simple: washout never goes near a gully, a road drain or a ditch.
The default position on responsibility
Unless your quote says otherwise, providing somewhere to wash out and dealing with what is left behind is the customer's problem, not the pump contractor's. That is worth checking, because it is the assumption on both sides that most often turns out to be different. Ask the question when you take the price, and get the answer in the same email as the rate.
What a workable washout arrangement looks like
- A designated, bunded or lined washout area away from drains, gullies, watercourses and any soakaway.
- Enough space for the hose and the hopper to be cleaned without the residue running anywhere.
- A plan for the solids: cured concrete waste is waste, and it leaves the site as waste.
- A plan for the liquid: it is not tipped down a drain, and it is not poured over the neighbour's border.
- On sites without a suitable area, a proprietary washout unit or skip brought in for the day, priced in advance.
Settle it in four lines before the pour
- Ask the contractor: do you carry a washout system, or do I provide a washout point?
- Agree the location on site, and check that nothing within reach of it drains to a watercourse.
- Agree who removes the residue, and confirm that anything leaving site goes with a properly registered waste carrier (gov.uk waste carrier registration).
- Put both answers on the order, next to the price. It takes one line and it removes the only common end-of-day dispute in pumping.
Site rules from a principal contractor may be stricter than anything here. On a managed site, the site rules win.