Car Wash Reclaim Tanks: Sizing Basics and Where Water Treatment Fits In

Search "car wash reclaim tanks" and you'll find a lot of tank sellers and not much engineering context. Here's the honest version: reclaim tanks, the plumbing that feeds them, and any discharge permitting around them are outside what we sell or advise on. What we do sell is the water treatment equipment that sits upstream and downstream of that tank - the filtration, softening, and RO stages that determine whether reclaimed water is actually usable for washing again.

What a Reclaim Tank Actually Does

A reclaim tank collects wash water after it's used - runoff from the bay, tunnel, or rinse arch - so it can settle and be pumped back into the system for reuse in pre-soak, high-pressure wash, or undercarriage stages. It's a holding and settling vessel, not a treatment device. Solids drop out, oil separates to some degree, but dissolved minerals, detergent residue, and hardness stay in the water unless something treats it before or after that tank.

Why Sizing Questions Come Up

Operators usually start asking about reclaim tank sizing when they're scaling from a single bay to a tunnel, or adding a second wash line. The tank has to hold enough volume to buffer between wash cycles without running dry, and it has to match the flow rate of the pumps pulling water back out. That's a plumbing and civil engineering calculation - tank shape, pump curves, retention time - and it's specific to your site layout. A local wash equipment installer or engineer who works with reclaim systems is the right resource for that math. We're not going to guess at your tank size from a blog post, and we'd rather say that plainly than pretend otherwise.

Where Our Product Line Actually Fits

The treatment stages we sell show up in two places relative to a reclaim loop:

Before Water Reaches the Reclaim Tank

Pre-filtration on your incoming supply line reduces sediment and scale-forming minerals before water ever gets used in the wash, which means less junk ends up settling in the reclaim tank in the first place. A whole-site pre-filter or a light commercial softener handles this on the intake side. If hardness is the main issue driving spotting or scale buildup in your equipment, that's a separate conversation covered in our Car Wash Buyer's Guide.

After Water Comes Out of the Reclaim Tank

This is the more common ask. Reclaimed water coming back out of the tank is settled but not polished - it still carries dissolved solids and residual detergent that make it unsuitable for a spot-free final rinse. If you're pulling reclaimed water forward for final rinse use, it typically needs to run through reverse osmosis to strip dissolved minerals before it hits the vehicle. Our Commercial Mid-Flow RO System (500-7,000 GPD) is sized for exactly this kind of application, and our RO Pricing & Sizing Guide walks through matching GPD output to your rinse arch flow rate.

Softening and Filtration Around the Loop

Depending on your source water, you may also need a softener ahead of the RO membranes to protect them from scale, or an inline filter on a secondary line feeding equipment that doesn't need full RO treatment. A Commercial Single Inline Water Filter works for a lower-flow branch line, while a Commercial Triple Inline Water Filter handles higher-demand lines needing multi-stage filtration in one housing. None of this replaces the reclaim tank itself - it's what makes the water coming into and out of it worth reusing.

The Practical Takeaway

Get your reclaim tank sizing and plumbing layout locked in with a wash equipment installer first. Once you know your flow rates and where reclaimed water re-enters your system, we can help you figure out what treatment stage - softening, filtration, or RO - actually needs to sit at that point in the loop. Our Car Wash Water Filtration Systems hub page breaks down the full range of options by application.

If you know your flow rates and where treated or reclaimed water needs to re-enter your system, request a quote and we'll help you size the right filtration, softening, or RO stage for it: get a quote.