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Compare and switch your car wash’s water supplier
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Home / Who we help / Car washes
Last updated August 2026
Who we help
Business Water for Car Washes and Forecourts
Water is the product in this trade. Every wash uses it, every bay drains it, and the gap between what comes in and what reaches the sewer is where the billing goes wrong.
You can switch retailer. Car washes have had that right in England since 2017. Most never have. This page covers where car wash water costs come from, how to switch retailer, and where overpayment usually hides.
| Wholesale supply | Comes from regional water companies (Thames Water, Severn Trent, Yorkshire Water, and others). |
|---|---|
| Contracting | Single sites can contract directly with retailers, and operators can contract centrally across every site. |
| Biggest savings levers | Return to sewer reviews, trade effluent banding checks and tariff reviews. |
| Recycling | Reclaim systems reuse a large share of wash water, and the billing should reflect the lower mains draw they create. |
| Market opened | England in 2017 and Scotland in 2008. |
| Licensed retailers | Around 20 are licensed by Ofwat to supply non-household water. |
Where the money goes
Why car washes pay more for water than they should
The usual story on a car wash bill is high volumes billed flat, a sewerage charge that assumes every litre returns to the drain, and a reclaim system the billing has never heard of. The five checks further down are where that shows up.
A wash site draws heavily and constantly through trading hours, and the volumes make every tariff decision count. Sites that have never compared retailers are paying a default price on one of the highest-usage profiles on any forecourt.
The sewerage side needs matching to reality. Water leaves on vehicles and to evaporation, reclaim systems recirculate a large share, and what does reach the drain carries silt and detergents under a trade effluent consent. Billing that ignores any of that overstates the charge.
Where it shows up
The five areas car washes overpay
Where car washes overpay and why it matters.
Return to sewer ignoring carry-off and evaporation
Water that leaves on vehicles or evaporates from the pad never reaches the sewer, yet default billing assumes most of it does. A corrected return to sewer allowance brings the sewerage charge in line with the site’s real discharge.
Reclaim systems invisible to the billing
A reclaim system cuts mains draw substantially, and the wastewater calculation should follow the new balance between fresh and recycled water. Older accounts often carry assumptions from before the system was fitted.
Trade effluent banding unchecked
Wash water carries silt, oils and detergents under a trade effluent consent with strength bandings. If interceptors and treatment have improved, the banding can be higher than the discharge justifies and is worth reviewing.
High volumes on a never-compared tariff
Volume magnifies everything on a wash site, including a poor unit rate. A site that has never compared retailers is running its biggest input on a default price.
Leaks lost in trading usage
Constant daytime draw hides leaks in the pipework and bays. Overnight meter readings when the site is closed are the fastest check an operator can run.
Results
Case studies
Recovered on historic surface water drainage charges that should never have applied.
Worth knowing
Consents, interceptors and what sits where
A wash site holds a water supply contract on one side and a trade effluent consent on the other, with interceptors and treatment sitting between them. The retailer bills for supply and sewerage, and the consent sets what the site may discharge and at what strength.
They are best reviewed together, since treatment upgrades change what the consent and the billing should say. The official market rules for business customers are published by Open Water, the body that runs the market.
The market
Can car washes switch water supplier?
Yes. England’s non-household water market opened to competition in April 2017 and Scotland’s opened in 2008, so every car wash and forecourt operator can choose a different water retailer. Wholesale supply still comes from your regional water company; only the retailer (the company that bills you and reads your meter) changes.
The 12 retailers below are all licensed by Ofwat to supply non-household water. Pricing, service and sector experience vary from retailer to retailer.
Choose your route
Routes to procurement
Three ways wash operators typically bring a new water contract in. Each comes with its own trade-off between control, effort and how sharp the price lands.
Direct with a retailer
The site signs straight with a licensed retailer. Best for a single wash that wants a sharper rate on high volumes. You handle the comparison and the switch yourself.
Operator contract across sites
Multi-site operators can put every wash on one central contract with one retailer. Efficient at volume, but each site is tied to whichever retailer was chosen.
Broker-led market test
A water broker compares the market for you, handles the paperwork and manages the switch from start to finish. Nothing changes in the bays.
Why choose The Business Water Shop
- Award-winning independent brokerage, not owned by or tied to any water retailer.
- Rated 5 stars on Google and 5 stars on Trustpilot by UK businesses.
- Experts with experience in business water for car washes, valeting and forecourt operators.
- We compare quotes from up to 14 licensed retailers.
- We handle the whole switch, from the comparison and paperwork to the supplier contact.
- One point of contact for multi-property portfolios.
Questions
Car wash water FAQs
Do car washes pay business water rates?
Yes. A wash site is a non-household customer, which is the open market we operate in. Whoever holds the supply account chooses the retailer.
We fitted a reclaim system. Should the bill have changed?
Mains draw falls when reclaim goes in, and the sewerage calculation should follow the new balance. If the account still reflects pre-reclaim assumptions, it is worth correcting.
What is in our trade effluent consent and why does it matter?
The consent sets what the site may discharge and at what strength, and the charges follow those bandings. Better interceptors and treatment can justify a lower banding than the one the site sits on.
Will switching disrupt anything on site?
No. A switch is paperwork rather than plumbing. There is no interruption to supply, no engineer visit and nothing changes in the bays.
Does a hand wash site differ from an automated one for billing?
The billing mechanics are the same. Volumes and discharge patterns differ, which changes where the money hides, but both run on a supply contract and, where they discharge to sewer, a consent.
We run several sites. Can they go on one contract?
Yes. Retailers operate nationally, so a group can consolidate sites in different wholesaler regions onto a single retailer, one contract and one point of contact.
How do I get a quote?
Send a recent water bill for the site. The SPID, annual volume and current retailer are all on it. We come back within two working days with an alternative quote and a flag if anything looks worth checking on effluent banding or allowances.
