Leaking spa - Ozone Check Valve
Adam MillerIf your spa is losing water and you’ve found drips around the ozone generator or the small black valve attached to the clear tubing nearby, the cause is almost always the same: a failed ozone check valve. It’s a common wear part, the replacement is straightforward, and most owners can do it in 20 minutes with a screwdriver and a new valve. This guide walks you through the procedure step by step, with safety notes and a few tips that make the job easier.
What the ozone check valve does
The ozone check valve sits at the end of the clear or white tubing coming out of the bottom of the ozone generator. Its job is to let ozonated air pass from the generator into the spa, while preventing water from flowing the other way. When the valve becomes defective, the seal fails and spa water starts working back through the tubing towards the ozone box — at which point you get a slow leak from the failed valve and, in worse cases, water inside the ozone generator housing.
Before you start: safety and warranty notes
- Power off: always shut off the spa at the breaker (or unplug a 13-amp plug & play model) before opening the equipment compartment.
- Lower the water level: if the leak has been going for a while, drop the spa water level below the ozone tubing entry point so you’re not fighting active flow during the replacement.
- Warranty check: if your spa is still under warranty, contact our support team before replacing the valve yourself — DIY replacement may affect warranty coverage on the ozone generator.
- Use the correct replacement valve: the new valve must be the right size for your tubing and rated for the ozone environment. Generic check valves are not a substitute.
Identifying the failed valve
Open the equipment compartment and locate the ozone generator. Follow the clear or white tubing from the bottom of the generator until you find a small black valve held in place by two metal clamps. If the leak is around this point, this is your culprit.
Replacing the ozone check valve: step by step
- Locate the ozone generator, which is typically near the control system in your spa’s equipment compartment.
(The image above shows the Toronto model. Layout may vary slightly between Canadian Spa models — the principle is the same on all of them.)
- Follow the clear/white tubing coming out of the bottom of the ozone generator to find the black check valve held in place by two metal clamps.
- Loosen the metal clamps with a screwdriver. Pull on the bottom section of tubing to expose one end of the black check valve, then pull on the valve itself to free it from the upper section of tubing.
- Fit the new valve, making sure the printed arrow on the valve points towards the spa and away from the ozone generator. This is the single most important detail — fitting it the wrong way round means it won’t work.
- Tighten the metal clamps back into position to secure the new valve. Don’t over-tighten — snug is enough; too tight can damage the tubing.
- Relocate the new check valve as high as possible within the spa cabinet — for example, attach it to the highest pipework under the rim of the acrylic shell. Mounting the valve high reduces the risk of water sitting in the tubing and back-flowing through the new valve over time. This small detail meaningfully extends valve life.
Watch the video walkthrough
For a full visual walkthrough of the replacement, watch the video below:
When to call an engineer instead
This replacement is generally a manageable DIY job. Call out a service engineer if:
- You’re not confident the leak is genuinely from the check valve (it could be the ozone generator itself, a tubing split, or another unrelated fitting).
- The spa is under warranty and you want to preserve cover on the ozone generator.
- The ozone generator itself is damaged or the tubing is brittle and crumbling.
- You’ve replaced the valve and the leak continues — the ozone generator may also need attention.
Our hot tub servicing team handles ozone repairs of this kind across the UK. While the engineer is on site, it’s worth asking for a wider check on the equipment compartment.
Frequently asked questions
How often does an ozone check valve fail?
It varies. Some valves last 5+ years, others fail within 18 months — partly down to ozone exposure, partly down to whether the valve was mounted high enough to avoid standing water. Mounting it high (step 6) is the single best thing you can do to extend its life.
Can I keep using the spa while waiting for a replacement valve?
Short term, yes — provided the leak is small and you’re topping up the spa as needed. But the leak will progressively get worse as the valve continues to fail, and water inside the ozone generator can damage the unit. Replace the valve as soon as you can.
Why does the arrow direction matter so much?
A check valve only allows flow one way. Fitted backwards, it stops the ozone generator from delivering ozonated air into the spa, and your sanitiser system stops working properly. The arrow must point from the generator towards the spa.
Can I use any check valve from a hardware shop?
No. Generic check valves aren’t rated for ozone exposure and will degrade quickly. Use the correct ozone-rated replacement, available through the team or via our support page.
What if my spa doesn’t have an ozone system?
Not all models include an ozonator as standard. If yours doesn’t, this leak source isn’t relevant — but other common spa leak points (the filter housing screws, jet bodies, pump unions) are. See our other leak guides for those.
Still leaking? Get in touch
If the leak continues after replacing the valve, or you’d rather have an engineer take a look, raise a support ticket and one of our agents will guide you through the next steps. For routine consumables and water care, our filter and water care range covers the items you’ll need across the year.
UK Spa Buying and Ownership Guide
After reading Leaking spa - Ozone Check Valve, many customers ask the same practical questions: what hot tub size fits best, how much does a hot tub cost to run, and which model gives the best long-term value in UK weather. The right answer normally comes from comparing insulation quality, jet layout, seating comfort, and ongoing maintenance support, not just headline price.
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For clearer next steps, use the links below to compare ranges, check current hot tub prices UK buyers are paying, and book support when needed.