Learning how to drain and clean your hot tub safely is an essential part of hot tub maintenance. A regular deep clean removes body oils, lotions, bacteria, biofilm, built up dirt and chemicals that a hot tub filter cannot remove on its own. This step by step guide explains how to drain your hot tub, clean the hot tub shell and refill your hot tub without putting unnecessary stress on the pump, heater, filters or hot tub's plumbing.
Prepare the area and switch off the power
Before you drain hot tub water, turn off the power at the control panel and then at the circuit breaker. Do not rely on the cover or a control setting alone: water and electricity need careful handling.
Remove the spa cover, check the cabinet for visible leaks, and make sure children, pets and bathers stay clear while the tub is empty. Choose a suitable existing drain that will not create puddles near the house, damage grass or affect plants, fountains or pools. Check local regulations before releasing spa water, particularly if you have recently added chlorine, bromine or shock treatment.
Gather supplies before you start: a standard garden hose or drainage hose, rubber gloves, soft cloth, damp cloth, dry rag, sponge, filter cleaner and a specialised hot tub cleaner.
Avoid household cleaners, as their residue can cause foam, cloudy water and skin irritation when the tub is refilled. Read the manufacturer’s instructions and each product label; specific instructions for one model can differ from another.
Flush the plumbing before draining
For a proper deep clean, use a pipe cleaner designed for hot tub plumbing before draining the water. Add the recommended amount to warm water, run the jets and circulation system for the time stated in the product instructions, then let the cleaner circulate through the pipes and plumbing lines.
This process helps release organic matter, oils, scale, bacteria and biofilm that can accumulate behind the shell. A pipe cleaner is especially useful when there are foul odours, poor water clarity, water pressure issues or a history of cloudy water.
Keep the cover open while the flush is running and watch for foam or residue. If the water is very dirty, a second flush may be needed; do not mix chemicals or pour more in without checking the label. The aim is to clean the lines effectively, not to make the hot tub drain faster by using too much product.
Use the drain valve safely
Locate the hot tub drain valve, sometimes called the drain spigot, primary spigot or drainage valve. Attach one end of the garden hose securely to the hot tub drain valve and direct the other end to the nearest drain. Open the drain valve slowly and let the water drain.
Gravity draining is the easiest way to drain your hot tub, although it can take several hours depending on the tub, hose length and water level.
A submersible pump is the fastest way to drain a hot tub when access is difficult or time matters. Place the submersible pump at the deepest point or deepest part of the footwell, attach its hose and monitor it throughout. Never leave a pump running dry.
When most of the water has gone, close the drain valve and use a wet and dry vacuum, or dry vacuum attachment, to remove remaining water from jets, pipes and filter compartment. This helps prevent trapped air and air locks during refill, particularly in winter months or colder climates.
Clean the shell, filters and cover
Once the tub is completely drained, wipe the interior shell with a soft cloth and a mild soap solution or specialised hot tub cleaner. Spray the cleaner onto the cloth rather than directly into the jets, then wipe the surface, waterline, seats and footwell.
A mixture of one part white vinegar to several parts warm water can help with light scale or residue, but follow the manufacturer’s guidance before using vinegar on a particular shell. Never use abrasive tools that could scratch the shell, damage seals or remove a protective surface.
Remove the filters from the filter housing and filter compartment. Rinse filters with a hose, working between each cartridge pleat, then soak them in filter cleaner if the product instructions recommend it. Replace filters that are damaged, waterlogged or remain clogged after cleaning.
Clean filters improve water flow, protect the pump and heater, and make it easier to balance new water. Wipe the spa cover inside and out, inspect it for mildew, mould, cracking and sun damage, then leave it dry before putting it back.
Refill, test and balance the new water
Put the hose into the filter housing before you refill. Filling through the filter compartment helps push air from the plumbing lines and reduces the risk of air locks.
Refill with fresh water to the correct water level, turn the power back on only when the tub is full, and check that the pump, jets and heater run normally. If water flow is weak, switch off the power and refer to the manufacturer’s instructions rather than forcing the system to run.
Use test strips to test pH, total alkalinity, total dissolved solids and sanitiser levels after the new water has circulated. Adjust water chemistry gradually using appropriate chemicals, then test again before a soak. Adding chlorine or bromine is not a substitute for balancing the water; clean water needs the right chemistry, circulation and regular cleaning to stay healthy.
Let the water reach the desired temperature, inspect for leaks around the cabinet and drain valve, and confirm the cover fits properly.
Keep the hot tub in tip top condition
Most hot tubs benefit from a drain and refill every 3–4 months, depending on use, water chemistry and how frequently the spa is shared with family or guests.
Regular cleaning, a clean hot tub cover, rinsed filters and prompt attention to signs of damage protect the equipment and help the tub stay ready for a safe, relaxing soak. If you have questions about the drain valve, plumbing, pump, chemicals or a persistent problem, contact a local dealer or hot tub engineer for advice.
The Hot Tub Engineer provides a range of Hot Tub Maintenance services in Maidstone and Kent, such as system inspections and chemical testing to help keep your hot tub in peak condition.
