Here’s the good news: The chemical additive you use to purify the water, whether it’s chlorine or bromine, will keep the water clean for three months or longer, depending on how frequently you use the tub, so there’s no need to empty it more often than that. But you will want to replace the water and start fresh every few months or so, or your hot tub will start to look and feel pretty grimy—or, worse yet, be contaminated by bacteria.
Methods for Draining a Hot Tub
There are three methods for draining a hot tub: through the drain spigot (a.k.a. drain plug), using a submersible drain pump, or with the help of a wet/dry vacuum. Before you start draining the tub, however, cut off the power supply so the jets and pumps can’t accidentally be during this procedure.
Also, check the ordinances in your area for any guidance or restrictions on discarding chemically treated water. Some towns may have laws on emptying pool or hot tub water into the street or within your own yard.
Using the drain spigot
Your hot tub comes equipped with a drain spigot, which is located on the outside of the tub, near the bottom rim. (Some models have two spigots, a primary and an auxiliary. The primary spigot is the one you’ll use to drain the hot tub; the auxiliary one is for bleeding the internal lines.)
If your drain spigot is located directly over a drain in the ground, just open the valve to allow the water to flow into the drain. If the drain or sewer is situated farther away, attach a garden hose to the spigot, position the other end of the hose over the drain, and open the valve. Note that if your drain or sewer is positioned uphill of your hot tub, you’ll need a submersible pump to drain the tub completely.
It should take one to two hours to drain the whole tub through the spigot. Depending on the contours of the tub, there will likely be some puddles of water left in the end. If you don’t own a wet/dry vacuum, which can be used to suck up these puddles, use your hands or a brush to scoop the water toward the interior drain.
Using a submersible pump
This is a faster way to drain a hot tub, since the pump acts to forcibly move the water out.
Start by attaching an outflow hose to the pump, then place the pump flat on the floor of the hot tub, at the center. See if the other end of the hose is long enough to reach the nearest drain or sewer. If it isn’t, attach a garden hose to the outflow hose to extend it. Then just turn on the pump and let it remove the water.
To take care of the leftover pools of water in the end, place the pump directly into a puddle to siphon the water. But keep an eye on the pump to make sure it’s always drawing water in taking in too much air can cause the pump to overheat.
Using a wet/dry vacuum
This method is slower than using a submersible pump, but faster than using the drain spigot.
Attach the wet/dry vacuum’s hose to the machine and place the open end of the hose in the water. Turn the vacuum on so water starts flowing through the hose. Once it does, turn the vacuum off and disconnect the hose from it. The water should continue to flow. Position the open end of the hose over a drain or sewer to let the water pour directly into it.
Once the water becomes too shallow to be siphoned out effectively, reattach the hose to the wet/dry vac and use it to draw out the remaining water. Make sure you vacuum up all the small pools of water at the end.