DIY Hot Tub For Less Than $50!


Updated on March 5, 2020  by Mary Bowen

DIY Hot Tub

This DIY hot tub makes use of a simple passive water heating technique. Water is heated by fire and pressure.

The cold water in the tub is sucked up into a copper or steel pipe that is coiled through a hot fire and is sent back to the top of the tub. The water cycles through until the tub reaches the desired temperature. All you'll need is:

  • Copper pipe, sand OR Steel pipe and elbow fittings
  • Two bulkhead fittings
  • Large animal stock tank
  • Fire ring (we used an old tractor wheel)
  • Copper fittings
  • Teflon Tape

You will also need: water, wood, matches, and a hot tub thermometer.

Fire Ring For Hot Tub

Copper Coil vs. Steel Pipe With Elbows

This winter our copper coil froze and burst so we re-adjusted our coil.

Instead we used 10 six inch sections of steel pipe and 10 elbows.

Not only was this coil easier to build but it heated the water much faster. The results were amazing and it works better than the previous set-up! You can build yours out of either type of pipe.

How To Make The DIY Hot Tub

First, if using copper pipe, pack the copper pipe full of sand and coil it so it can easy sit in the fire ring. GO SLOWLY! The trick to this is patience. Leave the ends of the pipe about two feet long. Or create a steel "coil" like this:

Homemade Hot Tub Heater Coil
  1. After the pipe is coiled and sits comfortably in the fire ring empty out the sand (copper pipe).
  2. Drill two holes in the trough. One near the bottom of the trough and the other near the top. Make them as far apart as the copper coil is in width and height.
  3. Using two bulkhead fitting, tape and copper fitting connect the pipe to the tub.
  4. Now set the the coil in the fire ring.  We used an old truck wheel that we got from Les Schwab. Fill the tub with water. Arrange your wood in the ring so the coils will get hot. Start your fire.

It takes about 4 hours to get the tub to 100 degrees.

Hot tubbing like this is an experience. It is fun to build the fire, to feed the fire, then finally enjoy the tub. All the waiting is worth it when in the evening you can jump in the hot tub right before you go to bed.

One word of warning, however, always stir your DIY hot tub before jumping in. The hot water all ends up in the bottom and, if unstirred, will unpleasantly surprise the first person to get in by being cool on the top and burning hot on the bottom. So...always stir.

If you live in a cold climate you should consider either making an easy way to drain the tub or some way to prevent the pipes from freezing and bursting. Enjoy you DIY hot tub!!


Matt Bowen lives in Northern California with his wife and ten children. He enjoys gunsmithing, swimming, and supporting his children in their endeavors which includes his acting debut as Sir Angus in Outlaws of RavenhurstMatt is a jack of all trades, master of none. With the help of Drinking with the Saints he has learned to make some pretty good cocktails.


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