Domakihub How to Drain a Hot Tub Safely and Quickly
A step-by-step guide to emptying, flushing, and refreshing your spa water.
Reviewed by Domakihub pool pros · 2026-06-23 · 4 min read
Draining your hot tub every three to four months is one of the single most effective things you can do to keep the water safe and the equipment running well. The video above walks through the full process visually, while this guide gives you the ordered steps, timings, and tips you need — especially relevant for holiday rentals, hotels, and private villas in Greece where a spa may be shared by many guests across a season. Done right, the whole job takes under two hours and leaves you with fresh, balanced water that protects both bathers and your investment.
Why Draining Matters More Than You Think
Hot tub water accumulates dissolved solids — sunscreen residue, body oils, minerals, and sanitiser by-products — that no amount of chemical dosing can fully remove. Over time the total dissolved solids (TDS) level rises to the point where the water becomes difficult to balance, foamy, or cloudy regardless of how much chlorine or bromine you add. Draining and refilling resets this baseline completely.
For properties in Greece this is especially relevant during peak summer. A villa or boutique hotel hot tub used by multiple guest groups in July and August can reach its TDS limit far faster than a privately owned spa used once a week. Scheduling a mid-season drain and refill between guest changeovers is good practice and reduces chemical costs over the season.
What You Need Before You Start
Gather your equipment first: a submersible pump (strongly recommended over the gravity drain plug alone — it cuts drain time from two hours to under 20 minutes), a garden hose rated for discharge, a second hose for refilling, a spa flush or line purge product, pH and alkalinity test strips, and your chosen sanitiser. You will also need a wet-dry vacuum for the last few litres that pool in the footwell after pumping.
Check local rules on where you can discharge the water. In most Greek municipalities you can direct it to a garden drain or storm drain, but avoid discharging heavily chlorinated water directly onto plants or into a septic system without diluting first. If the water has been treated with a spa flush product, let it dilute with fresh tap water as it drains.
How to Drain Your Hot Tub: 5 Steps
- 1
Run a line flush the night before
Add a spa line flush or pipe purge product to the water while the jets are still running. This dissolves biofilm and organic build-up inside the plumbing lines so it gets expelled during the drain rather than sitting in the pipes until next fill. Run the jets on high for 30 minutes, then leave it overnight with the cover on.
- 2
Switch off power at the breaker
Before touching anything else, turn off the hot tub at the main circuit breaker — not just the control panel. This protects the pumps, heater, and any electronic components from running dry. Never skip this step, even for a moment. Confirm the display is completely dark before proceeding.
- 3
Connect your submersible pump and drain
Place the submersible pump in the deepest part of the footwell, connect the discharge hose, and direct it to your chosen drain point. Switch the pump on and let it run. A good submersible pump will empty a standard 1,000-litre spa in 15 to 20 minutes. Once the water level is too low for the pump to continue, open the spa's built-in gravity drain plug to release the remaining water, then use a wet-dry vacuum to remove the last puddles from the footwell and seat channels.
- 4
Scrub the shell while it is empty
Spray the interior with a non-abrasive spa shell cleaner or a diluted white-vinegar solution and scrub with a soft cloth or sponge. Pay particular attention to the waterline ring (a combination of oils and calcium deposits), the jets, and any rubber gaskets. Rinse thoroughly with fresh water and vacuum out the rinse water. Do not use household bleach or abrasive pads — they can damage acrylic and void warranties.
- 5
Refill, balance, and restart
Insert the refill hose into the filter compartment rather than directly into the footwell — this reduces air locks in the plumbing. Fill to the manufacturer's recommended level (usually mid-skimmer). Once full, restore power at the breaker, let the system circulate for 30 minutes to stabilise temperature, then test and adjust pH (target 7.4–7.6), total alkalinity (80–120 ppm), and sanitiser level before anyone enters the water.
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FAQ
- How often should I drain my hot tub?
- Every three to four months is the standard recommendation for a privately used hot tub. If the spa is used heavily — as in a holiday rental or hotel setting — drain and refill every six to eight weeks, or any time the water becomes persistently cloudy or foamy despite correct chemical levels.
- Can I drain a hot tub using just the built-in drain plug without a pump?
- Yes, the gravity drain plug will eventually empty the spa, but it typically takes two hours or more for a standard 800–1,200 litre hot tub and leaves several litres pooled in the footwell that you still need to mop up. A submersible pump costing €30–€60 makes the job five times faster and is worth buying if you drain more than once a year.
- Where should I discharge the hot tub water in Greece?
- Most of the time you can direct it to a garden storm drain, a municipal drain, or let it soak into a gravel area away from plants. Avoid discharging heavily chlorinated water directly onto vegetation or into a septic tank. If you used a line-flush product, let the water dilute with fresh tap water as it drains to reduce chemical concentration.