Draining, or emptying your spa or hot tub, is necessary every 2-4 months, to reduce the amount of dissolved solids in the spa, and any germs or “baddies” that may have built up some resistance to the spa chemicals.

Draining is also sometimes preferable to intensive shock treatment, which can be harmful over time to spa seals and finishes. I prefer to drain more often, and use fewer harsh chemicals, when possible.

There are some considerations for draining a hot tub, including: local water restrictions, spa water chemistry and in some areas – water discharge regulations. If you plan to leave the spa drained for an extended period of time, I have some tips below for that too.

When to Drain A Spa or Hot Tub

Spas with very high use, commercial or public spas, may need to drain every few days to keep maintain water health. For private spas or hot tubs, with say, 9 spa sessions per week (3 users, 3x weekly), your spa water will last longer, up to 4 months between changes.

Some spa owners will drain for persistent cloudy water, or after a heavy use weekend by many people, or if they’ve managed to let the spa “go” – for some time without sanitation or filtration. I’ve drained my spa for all of these reasons at one time or another – otherwise, it’s every 3 or 4 months.

“When in doubt, drain it”, is my usual advice, or when the spa chemistry is really bad – “water is cheaper than chemicals!”, is something I might say.

How to Drain A Spa or Hot Tub

Before draining the spa, or at least twice per year, use a Spa Purge type chemical to remove biofilm and hidden “funk and gunk”. If you’ve never use one of these spa pipe cleaners, you’ll be amazed at the amount of gross, brown bio-gunk that it foams to the surface. Spa Purge is a name of one spa biofilm remover, I get great results using Jet Clean, which is a lot cheaper.

After circulating Jet Clean for around an hour, I am ready to drain the spa. Some spas have a handy external spigot to connect the hose, but mine is inside, and not in the most convenient location. After hooking up a permanent hose of the perfect length, I now just reach inside the cabinet and pull out the hose.

Shut off the Power. At the main switch, so your equipment timer won’t turn the pumps on during the drain and refill.

Gravity Draining with a hose takes some time, my spa takes about 3 hours to drain. I come out every hour and move the hose to a new location in my backyard. You can also use a small submersible pump, like a pool cover pump, to drain the spa in 15-30 minutes. When it’s about halfway down, I spray down the exposed walls with my garden hose, and again when empty.

Spa Siphon – If you have no spa drain spigot, and no utility pump, you could drain by siphon, if you have an area nearby that is lower than the hot tub. Duct tape a Crescent wrench to the end of a hose and place it in the bottom of the spa. Starting at the point where the hose comes out of the water, push the hose straight into the water, and coiling it underwater. Fill the entire hose up in this manner, and then cap the end of the hose with your thumb and quickly pull the hose to an elevation lower than the spa floor. Release your thumb and water should begin to flow.

Spa Water Use and Hot Tub Discharge Restrictions

Drought is a real reality in areas across the country. If your city is experiencing severe drought, it may put in place mandatory water restrictions, that may restrict draining and refilling your spa or hot tub.

In addition to this, most cities and towns have some regulations regarding how to discharge or drain a spa, hot tub or pool. Here are some general guidelines, your city may be different.

• Water should have a balanced pH level
• Sanitizer level should be very low
• Don’t pump to the Sewer, but “Infiltrate” around the yard
• Don’t pump near any streams or tributaries

Leaving your Spa Drained for an Extended Period

Wooden hot tubs will dry out without water in them, so it is not recommended to leave them dry for longer than a few days, just long enough for repairs or relocation.

If you know you will be unable to maintain a non-wood spa for months at a time, it will be best to drain it, to prevent biofilm and bacteria build-up.

As the spa is nearly drained, turn on the blower, to clear out the lines (you may want to put the spa cover on first!). Use a powerful wet/dry vac to blow air through the pipes – from the skimmer and spa jets. A small air compressor can also be used, (with low pressure), connected into the pump drain plug. This is important, to prevent standing water from developing into a bacterial mess, inside of the hoses or equipments. The same process is used to winterize a spa or hot tub.

Remove the drain plugs from the equipment, and leave all drains open. Remove the spa filter and store indoors. Wipe down the inside of the spa, with a  sponge or towel to remove any remaining water. Put on your spa cover on to keep it clean.

Carolyn Mosby
Hot Tub Works