Car wash cost per car: auditing oil, chemicals and reclaim water

Ask most operators for their car wash cost per car and you’ll get an estimate. Chemical drums, oil, water and power all arrive as invoices and utility bills at the end of the month, and none of them say which cars they were spent on. If a pump starts over-dosing or the reclaim system starts losing ground, the first sign is often a bill that’s higher than last month — weeks after the problem began.

A reporting audit ties those inputs to the cars that actually went through, by site and by day. This post covers the three things owners ask us about most: oil, chemicals, and reclaim water against fresh water.

Start with an accurate car count

Everything here is measured per car, so the car count has to be right. Your controller — Sonny’s CarWash Controls, TunnelWatch or similar — gives one count; your POS gives another; plate reads at the entry give a third. Where they disagree is worth knowing about on its own. The audit uses the most reliable count for each site and flags the days when the sources don’t match.

Chemicals per car

Each chemical — presoak, soaps, wax, tyre shine, drying agent — is dispensed by the controller, and most setups log how much. The audit puts that against cars washed, broken down by package, because a top package uses more product than a basic one.

What you’re looking for is change. Say a site’s presoak use per car creeps up week over week while the wash mix stays the same. That could be a dosing pump drifting, a leaking line, a setting someone changed, or a new drum at a different concentration. The report can’t tell you which, but it tells you that week which site and which chemical to check — rather than leaving it until the next invoice.

It also lets you compare sites fairly. Two washes running the same menu shouldn’t use very different amounts of product per car; if they do, there’s a reason worth finding.

Oil

Oil is easy to forget because it doesn’t show up on the menu. The conveyor, hydraulics and other equipment all need it, and top-ups tend to be recorded on paper if at all. Logging every top-up and purchase by site, and putting it against hours run and cars washed, turns oil into a number you can watch. A site that needs topping up more often than it used to may have a leak or a part wearing out — and a maintenance flag is cheaper than a breakdown on a Saturday.

Reclaim water against fresh water

If your wash reclaims water, the question is how much of each car’s water is coming from reclaim and how much from the mains. Meter readings for fresh water drawn and water reclaimed, put against cars washed, show that split each day.

The useful part is seeing it move. A reclaim system that’s slowly losing ground — a clogged filter, a pump wearing out, a tank needing service — shows up as fresh water per car rising while reclaim falls. Seen on a daily report, that’s a service call. Seen on the utility bill two months later, it’s two months of extra water already paid for.

What counts as a good split depends on your equipment, your climate and any local rules you operate under, so we don’t set a target for you. The report shows your own trend, by site, against your own normal.

Building up your full car wash cost per car

Once inputs are tied to cars, other reports come easily:

• Total cost per car by site — chemicals, water, power and labour together.
• Margin on each unlimited plan, given how often its members actually wash.
• Tunnel downtime and what caused each stop.
• Labour hours against cars washed.
• Free washes and discounts by employee.

Every report is built to your sites and the metrics you care about — if you can define it, it can be reported.

Getting the data in

Most of this already exists somewhere: dispense logs in the controller, transactions in the POS (DRB SiteWatch or Patheon, Washify, ICS, AMP), plate reads from the cameras, and meter readings. The work is pulling it together on a schedule and putting it in one report that lands in your inbox in the morning. Where something isn’t recorded today — oil top-ups are the usual one — the first step is simply starting to log it.

Why it’s worth doing

None of this changes how the tunnel runs on its own. What changes is how fast you find out when something drifts. For how the car count and stop data come off your cameras, see what the cameras at your wash can tell you. The same plate reads also show which members are washing less, which is where a car wash marketing audit starts. For the full list of reports we build, see the reporting and audits section of our car wash page.

Common questions

How do I work out my car wash cost per car?

Tie each input — chemicals, oil, water, power and labour — to the cars that actually went through, by site and by day. That starts with an accurate car count, so compare your controller, your POS and plate reads, and flag the days they disagree. Once inputs sit against cars, total cost per car by site follows.

How much reclaim water should my car wash use?

It depends on your equipment, your climate and any local rules you operate under, so there isn’t one target to aim for. What matters is your own trend by site: fresh water per car rising while reclaim falls is the sign of a clogged filter, a worn pump or a tank needing service.

Can I track chemical use per car from my tunnel controller?

Usually, yes. Each chemical is dispensed by the controller — Sonny’s CarWash Controls, TunnelWatch or similar — and most setups log how much. The audit puts those dispense logs against cars washed, broken down by package, and flags when use per car starts to change.