Leaking spa - leaking from Filter housing screw

A small leak near your filter area is one of the more common spa repair questions we get — and the good news is that it’s usually a straightforward fix. The most likely cause is the screws that hold the filter housing lid in place: over time water can find its way down past the screw threads and emerge as a slow seep around the housing. This guide walks you through how to fix it safely, with a few notes on when it’s worth calling out an engineer instead.

Before you start: a few important notes

• Power off: always shut off the spa at the breaker (or unplug a 13-amp plug & play model) before working around any wet area or removing components.
• Warranty check: if your spa is still under warranty and the leak appears to be a manufacturing fault, contact our support team first — DIY repairs may affect warranty coverage on that component.
• Confirm the source: dry the area thoroughly with a cloth, watch for 10–15 minutes with the spa filled, and confirm the water is genuinely coming from around the filter-housing screws. Small leaks elsewhere can look similar.
• Use the right silicone: a clear neutral-cure silicone sealant suitable for wet environments is what you want. Avoid acetic-cure silicones (the strong vinegar smell), which can corrode metal fittings.

Identifying a filter-housing screw leak

If your spa is leaking from an area immediately next to the filter housing, there’s a good chance the leak is actually coming from the screw holes that hold the filter housing lid in place — not from the housing itself or the plumbing behind it.

The screws sit in the moulded acrylic, and the foam insulation behind the shell can wick moisture if the seal around the screw fails. The result is a small but persistent leak that often only shows up around the housing or on the foam side once you open the equipment compartment.

How to fix it: step by step

1. Lower the water level below the screws that hold the filter housing lid. You don’t need to drain the whole spa — just enough to expose the screws above the waterline.
2. Allow 24 hours for the area to dry out completely. This is the step most people skip — silicone won’t bond properly to a wet surface, and the repair will leak again within weeks. Patience here pays off.
3. Remove the screw using a Phillips-head screwdriver. Set it aside somewhere clean and dry.
4. Apply a layer of silicone around the screw hole and the surrounding sealing surface. Don’t be stingy — a proper bead is what gives you a watertight seal. Wet-area neutral-cure silicone is the right product.

5. Replace the screw through the silicone, pressing it firmly back into position. Wipe away any excess silicone around the area, leaving a small bead intact for the seal. If the screw hole is too large for the original screw to grip properly, you may need a slightly larger stainless steel screw.

6. Wait at least 24 hours for the silicone to fully cure before refilling the spa. Cured silicone gives you the watertight seal; partially cured silicone gives you a repeat leak.

Watch the video walkthrough

For a full visual walkthrough of the repair, watch the video below:

When to leave it to a service engineer

This is generally a manageable DIY repair for any owner comfortable with a screwdriver and a tube of silicone. Call out a service engineer instead if:

• You’re not confident the leak is genuinely coming from the filter housing screws (it could be a different fitting behind the shell).
• The spa is under warranty and you want to preserve cover on the affected component.
• The screw hole has stripped or the surrounding acrylic is damaged.
• You’ve attempted the repair and it’s leaking again — there may be a second leak source elsewhere.

Our hot tub servicing team handles repairs of this kind across the UK. A service call is also a good opportunity for a wider check-up if your spa hasn’t been inspected in a while.

Frequently asked questions

How can I tell if my leak is from the filter housing screws or somewhere else?

Dry the area thoroughly, then watch the spa with the water at normal level for 10–15 minutes. If the seep starts again specifically around the housing screws (not the housing-to-shell seal, not the plumbing behind it, not the cover), the screws are the most likely culprit.

What kind of silicone should I use?

A clear neutral-cure silicone sealant rated for wet environments and submersion. Standard kitchen/bathroom acetic-cure silicones (the strong vinegar-smell ones) can corrode metal fittings — avoid those.

Can I refill the spa straight after applying silicone?

No — give it a full 24 hours to cure. Refilling early means the silicone won’t seal properly and you’ll be back where you started within a couple of weeks.

Will this fix void my warranty?

Possibly — depends on the model, the warranty terms and the nature of the original leak. If your spa is still under warranty, contact our support team before doing the repair so the situation can be assessed properly.

The leak isn’t around the screws — where else could it be coming from?

Other common leak points include the filter housing seal itself, the jet body fittings, the union connections at the pumps, the heater unions, and the cabinet drain valve. Some of these are accessible DIY repairs; others need an engineer.

Still leaking? Get help

If the issue persists after the repair, or you’d rather have it looked at properly, raise a support ticket and one of our agents will guide you through the next steps — or arrange a service visit if needed. For routine maintenance and parts, our filter and water care range covers most consumables you’ll need across the year.

UK Spa Buying and Ownership Guide

After reading Leaking spa - leaking from Filter housing screw, 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.

Canadian Spa Company UK supplies hot tubs, swim spas, saunas, replacement hot tub covers, filters, chemicals and accessories with nationwide delivery. If you are planning to buy a hot tub UK homeowners use year-round, shortlist models by intended use first: daily recovery, social entertaining, or family wellness. Then compare power requirements, cover quality, and service access so ownership stays simple over time.

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.

• Hot tubs for sale in the UK
• Swim spas and dual-temperature options
• Home sauna range and infrared options
• Replacement hot tub covers
• Hot tub filters and water care essentials
• Hot tub servicing and repair support