Operating your drain valve to empty your spa part 2

Xavier Labelle

Changing the water in your hot tub is one of the few maintenance tasks you really do need to do — typically every 3–4 months for a home spa, more often for heavily used or commercial spas. Fortunately, the drain valve at the bottom of your spa is designed to make it straightforward. This guide walks you through the procedure, plus a few UK-specific notes on where to drain the water to and how to refill cleanly.

Watch the video walkthrough

How the drain valve works

The drain valve at the bottom of your spa has a simple but well-designed locking mechanism. When the valve is extended outwards, the water is held back so you can attach (or remove) a garden hose without anything spilling. When the valve is pushed back in and twisted, the water flows. That two-stage operation is what makes it safe to thread a hose on without flooding the cabinet base while you do it.

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 draining. Running the heater or pumps dry will damage them.
  • Cool the water down: hot water shouldn’t be drained straight onto a lawn or borders. Either cool the spa to ambient temperature for a few hours before draining, or direct the discharge somewhere it can’t damage planting.
  • Choose a sensible discharge point: see the UK drainage section below.
  • Have a clean hose ready: a standard UK garden hose with a male threaded end is what fits the drain-valve cap.

Step by step: emptying the spa

  1. With the drain valve extended outwards, unscrew the cap from the middle of the valve.
  2. Screw the male threaded end of your garden hose into the now-exposed valve, and run the other end of the hose to wherever you’ve planned to send the water.
  3. When you’re ready, push the valve back in and twist it to release the water.

Gravity does the work from here. A typical home hot tub holds 800–1,400 litres and takes a few hours to fully drain. There’s no need to stand and watch it; check back periodically, and turn off the valve once the spa is empty.

Where to drain the water in a UK garden

This is the bit that catches new owners out. UK gardens often slope, soils don’t always drain quickly, and you don’t want a few hundred litres of treated spa water destroying a freshly seeded lawn or a rose bed. Sensible options:

  • The household foul drain — usually the safest discharge point. Most UK properties have a foul-water drain in the back garden you can hose into.
  • A surface-water drain or soakaway if your area has one and your local authority allows it.
  • A stretch of paving or paved patio that slopes away from the house and any planting — useful if the water is well-cooled and chlorine/bromine has dissipated (give the spa 24–48 hours after stopping sanitiser dosing before draining if you’re going this route).
  • Avoid: draining onto lawns, borders, vegetable beds, ponds, or anywhere the water will pool. Spa chemistry is fine in a swimming pool quantity but harsh on garden plants in concentration.

Check your local water company’s guidance if you’re unsure — most accept hot tub water into the foul drain.

While the spa is empty

This is the ideal opportunity to do a few maintenance jobs that are awkward when the spa is full:

  • Wipe down the shell with a non-abrasive spa-safe cleaner. Avoid household scrubbers — they can scratch the acrylic.
  • Clean the filter housing and rinse or replace your filter cartridges. A clean filter is the single biggest difference-maker for water clarity on the next fill.
  • Check the cover seals and underside for any moisture damage. If your cover is sagging or no longer sealing properly, it’s worth considering a replacement cover before you refill.
  • Wipe out the footwell and around the drain valve while everything is dry and accessible.

Refilling cleanly

When the drain is complete, close the valve, unscrew the hose, and replace the cap. To refill:

  1. Remove the filter cartridges from the housing temporarily.
  2. Place the garden hose inside the filter housing rather than into the open shell — this helps prime the pumps and minimises trapped air.
  3. Refill until the water reaches the recommended fill line on the spa.
  4. Refit the clean filter cartridges.
  5. Restore power and let the spa run a full priming cycle. Check for any leaks at the drain valve and unions before letting the spa heat up.
  6. Balance the water chemistry from scratch — alkalinity, pH, then sanitiser. Don’t get in until everything is in range.

Frequently asked questions

How often should I drain and refill my spa?

Every 3–4 months is the standard for a home hot tub used a few times a week. More often for heavily used spas, holiday lets, or any spa where the water is starting to look or smell off despite balanced chemistry.

How long does it take to drain a typical hot tub?

2–4 hours for most home spas via the gravity-fed drain valve. Larger spas or longer hose runs can take longer. A submersible pump can speed things up if you have one, but the drain valve is enough for most owners.

Can I drain a spa straight onto the lawn?

It’s not recommended unless the water is cool and the chemistry has fully neutralised. Spa water in concentration can damage lawns and plants. The foul drain or a sloping paved area is safer.

What if my drain valve won’t extend or twist?

The valve can stiffen with limescale or grit if the spa hasn’t been drained in a while. A bit of gentle persuasion usually frees it. If it’s seized completely, contact our support team or arrange a service visit — don’t force it.

Do I need to drain the spa to clean the filters?

No. Filter cleaning is a separate, more frequent task — every 2–3 weeks for a routine rinse, monthly for a chemical soak. Full drain and refill is the every-3–4-months reset.

A simple job, done properly

The drain valve is one of the most well-engineered parts of your spa — designed to make a routine job painless. Get the discharge point right, take the chance to clean while the spa is empty, and you’ll be back to balanced water within a few hours of refilling. If your spa has been a while between services, a full drain is also a good opportunity to book a service visit so an engineer can check the components you can’t see.

UK Spa Buying and Ownership Guide

After reading Operating your drain valve to empty your spa part 2, 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.

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