Can You Fill A Hot Tub With Hot Water? [Rain, Hose, Cold]

Known for being great ways to relieve sore muscles, unwind, and relax, hot tubs are meant to be filled with water. However, certain processes must be observed in order to ensure a hot tub’s proper functioning.

As discussed below, there is a right and wrong way to fill a hot tub, specific water temperatures should be adhered to, and proper maintenance routines should be put in place to guarantee the longevity of a hot tub and the safety of its users. 

Can I Make my Hot Tub Hotter than 104 ?

The maximum temperature setting on any hot tub is 104 F. However, this does not mean you should allow the water’s temperature to reach this level.

In fact, the United States Consumer Product Safety Commission (CPSC) has deemed a temperature of 100 F to be safe for adults and advises children to be closely monitored under such a high temperature.

Furthermore, the CPSC strongly advises that users never, under any circumstances, allow hot tubs to reach a temperature of 104 F due to safety reasons. Water over 104 F can easily raise one’s body temperature to dangerous levels causing stroke and even death.

Additionally, it should be noted that pregnant women should keep water no warmer than 100 F as temperatures 102 F and higher may cause damage to their fetus.

Why is it not Really a Good Idea to Fill your Hot Tub with Warm Water ? 

Filling a hot tub with warm water may seem like the logical thing to do but doing so may cause severe damage to the lining of the hot tub. The maximum temperature a hot tub is meant to reach is 104 F.

However, the minimum temperature for a household hot water storage tank is 160 F. As a result, pouring hot water straight from a storage tank exposes the hot tub to temperatures at least 20 F higher than they are designed to handle and creates a likelihood for cracking, blistering, and other damage that likely is not covered by any insurance policies. 

Can you Fill a Hot Tub with Hose Water?

Hot tubs can be filled with hose water fairly easily. However, users should be aware of the potential of airlocks, also known as air bubbles, that may form within the plumbing of the hot tub. One or more of these bubbles may cause damage to jet and circulation pumps causing the hot tub to malfunction. 

To prevent airlocks from forming, users can simply utilize a fill pipe instead of placing the hose directly into the hot tub. Each hot tub varies, but information on fill pipes and how to use them should be easily found within the owner’s manual of each individual hot tub. 

Can you Fill a Hot Tub With Cold Water?

While not exactly common, hot tubs can be filled and used with cold water. Actually, some hot tubs even have a cool setting. However, given the fact that it takes hot tubs a bit of time to cool down, it is not realistic to think that one can easily switch back and forth between hot and cold temperatures.

Instead, it is better to decide on a certain temperature and stick with it for an extended period of time. While there are many methods of cooling a hot tub and keeping it cold, the most important thing to note is that unlike hot water, filling a hot tub with cold water will pose no risk of damage. 

Can you Fill a Hot Tub With Rain Water ?

Rain water will not cause any immediate damage to a hot tub but will create additional maintenance work in order to keep the hot tub in pristine and usable condition. This is due to the acidity of rainwater, particularly within North America. 

High pH levels may cause a hot tub’s water to become cloudy and creates calcium buildup. This calcium can create yellow flecks in the water and impair jet performance.

Additionally, rainwater may throw off a hot tub’s alkalinity. It should be noted that low alkalinity is more dangerous than high alkalinity as it causes rapid pH fluctuations within the water. Unbalanced levels of alkalinity can be spotted by a green tinge to a tub’s water or a drying sensation of one’s skin after use of the hot tub. 

Luckily, there are products that can be purchased to treat and stabilize a hot tub’s pH and alkaline levels. 

Is Rain Water Good for Hot Tubs ?

While rain water does not necessarily harm hot tubs, it cannot be described as being good for them either. Small amounts of rainwater may help keep a hot tub full with no harm done to the water, hot tub, or users.

However, as previously stated, large amounts of rainwater can have negative impacts on a hot tub’s water quality, and if left untreated, may cause damage to the hot tub. 

So, What’s the Conclusion? 

Overall, hot tubs are a great investment for those looking for a great way to relax and enjoy the outdoors. They are generally easy to fill and drain, and owner’s manuals provide specific and easy to follow instructions for each hot tub. Furthermore, when safety guidelines are adhered to, minimal hot tub maintenance is needed.

The trickiest task is likely balancing alkalinity and pH levels particularly if large amounts of rainwater enter a hot tub. However, there are many ways to avoid such an occurrence, and many products are available to make the balancing process easy.

This being said, it is important for one to do their research before filling, draining, or using a hot tub. However, information, especially that found on the internet, is abundant, and the guidelines given are pretty straightforward.

They are put in place to ensure the utmost safety of users and the ultimate enjoyment of hot tubs and the water in them. 

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Emily Williams

Emily is a passionate Hot Tubs researcher who loves writing about all things Hot Tubs! She has years of experience and a knack for simplifying complex concepts, these articles are here to answer all your burning questions in a simple and easy to read style.
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