How to fill up a hot tub with water correctly

1 October 2014  |  Superior Wellness

Getting the water into the hot tub sounds simple but if you do it wrong you can cause damage to the components that might be expensive, the following are tips relating to filling your hot tub up with water.

Using hot water to fill your tub

In most cases it is advised not to fill your hot tub or spa directly with hot water but if you do, make sure the water temperature is not excessive, for the best result remove air lock (see below) then increase the cool water in the main water area by putting the hot water into cool which will slowly increase the tempreture.

Pre-filtering your tap water

Using a pre-filter can be useful for some people in some areas, but not to all,

What is a pre-filter?

These useful little items are the equivalent similar a normal hot tub filter but they work in a slightly different way, they are designed to take out excess minerals like calcium that will make your water cloudy and scaly, they connect to your hose pipe usually by a hozelock type connector.

If you have problems with scale or high levels of minerals then a pre-filter is an essential item.

Where to fill the water up to

The height of the water is difficult to define on hot tubs and spas, but you can use basic logic to get it right.

  1. make sure it covers all the jets,
  2. It needs to be above any water level sensors
  3. It should always be 1" or below the pillows (Its rots the rubber)
  4. Never let air be sucked into the heater circuit (always fill at least 2" above the filters)
  5. Never switch a hot tub on when the water is half full to start heating

Where to put the hose.

When filling up a hot tub from empty it is important to get as much air out as possible from the system.

The most important system in any hot tub is the one that heats the water and circulates, if this has air inside when its switched of the safety defences will not function correctly and you could end up burning out your hot tub heater or the circulation pump.


This article was written by Jon Pennington from Hot Tub Help Ltd for Hot Tub DIY - Hot Tub Parts Cornwall