How to drain a hot tub

Items you need ready

Have all your supplies gathered before you open the drain. Leaving a tub half full without a hose nearby creates a muddy mess.

• A submersible pump (a small pump that goes into the water), or a garden hose able to reach a drain
• Get a cleaner made to flush the lines.
• Grab a cleaner for spa shells along with soft rags.
• A filter cleaner plus a bucket large enough to soak the filter
• Your startup chemicals for fresh water and test strips are also needed.

Steps for how to drain a hot tub

1. Start by flushing the lines. Add a line flush cleaner to the old water, then turn on the jets. One brand calls for 1 pint and running jets for 1 hour, as Leslie's explains. This breaks up slime inside the pipes so it washes out with the old water.
2. Switch off the power at the breaker. Never let the heater or pumps run while the tub is empty. For a plug-in model, pull the plug and keep the cord away from the water.
3. Remove the filters from the tub. Put them aside for cleaning while the water drains out.
4. Open the spout used for draining. You will find it near the bottom of the cabinet. The threads are plastic and may crack, so screw the garden hose on gently.
5. Place the hose so it runs downhill toward a drain. Since water cannot flow uphill from the tub, some would remain inside otherwise.
6. A submersible pump is another option. Place the unit on the tub floor, route its hose to the drain, and turn it on.
7. Open the secondary drain if your tub includes one. Roughly 1 gallon (4 litres) more drains from the thin side lines.
8. Once the tub is empty, give the shell a clean. Use a soft damp rag with spa shell cleaner to wipe it, then rinse. Aim the hose at each jet to flush out debris the cleaner loosened.
9. Clean the filter next. Use the hose to rinse between the pleats after soaking it in filter cleaner per the label.
10. Shut all drains and replace the caps. Your tub is now ready for filling.

Keep the power off until the tub fills up. Damage to pumps and heaters may occur if power reaches an empty tub.

Use the filter well to refill

Place the hose in the filter well, the pipe beneath the filter, not in the open tub. This pushes air out of the pipes as water rises. Top filling might trap an air bubble known as an airlock, which stops pumps.

Water should reach about 1.5 inches (4 cm) over the highest jet when filled. Cold tap water is required, not softened or hot water. Draining via the spout takes about as long as refilling does.

Only restore power at the breaker when the tub is full. Check that jets push hard after running them on high for 1 minute. Surging or weak jets indicate trapped air or low water levels.

Balance the new water

You must balance fresh tap water before anyone uses the tub. Adjust alkalinity first to about 125 ppm (parts per million) to keep pH steady. Sanitizer goes in last after adjusting pH to 7.4 to 7.6.

While adding each chemical, run the jets and test in between. Find doses and the complete list for your size on the startup chemicals page.

Add chemicals one at a time directly to the water, never mixing them in a cup or bucket.

What does filling a hot tub or Jacuzzi cost?

Your local rate times tub gallons gives the cost since water is billed by volume. Look at your water bill for the rate, often listed per 1,000 gallons. If old water enters a household drain, include the sewer rate as well.

Take your gallons, divide by 1,000, and multiply the result by the rate. At $10 per 1,000 gallons, the cost to fill a 400 gallon (1,514 litre) tub is $4. This method applies to any hard tub or a Jacuzzi. Unsure about the size? Check how many gallons your hot tub holds.

Since heating costs more than the water, fill on a day when there's time for it to warm.

Where to send the old water

Aim for a drain connected to the sewer, like a floor drain or utility sink. The guide from Jacuzzi recommends sending it to the sanitary sewer.

High levels of chlorine or bromine in the water can damage plants and grass. Leave the tub covered for several days and stop adding chemicals before you water the garden with it. Check the water first, and use it only if the strip shows little or no sanitizer.

Regulations for street drains vary by town. Contact your town or water company before draining it that way.

How often to drain hot tub water?

According to Hot Spring and Jacuzzi, fresh water is needed every 3 to 4 months for most hard tubs using chlorine or bromine. Hot Spring's salt system can extend that time to about a year.

Inflatable models hold less water, meaning they need changing sooner. Bestway recommends every 1 to 3 months, while Intex suggests every 2 to 3 months. Heavily used tubs need changes even sooner, so work out your own date based on your gallon count and number of bathers.

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