The simplest DIY cold plunge is a tub deep enough to sit in up to your neck, filled with cold water and ice. A bathtub works for a first try; a 100-gallon stock tank on a solid base is the most common backyard build. Add a floating thermometer, a non-slip mat and a cover. If you want the water cold every day without buying ice, the next step is a pump, filter and chiller, which is where a DIY build gets more complex. Check with your doctor before you start, and never plunge alone.
This guide compares the main DIY options and their costs, walks through a stock-tank build step by step, and explains when a finished cold plunge tub is the better buy.
DIY cold plunge options at a glance
| Option | How it works | Cost guide |
|---|---|---|
| Bathtub with ice | Fill with cold tap water, add ice, drain after | Ice only: HomePlunge estimates 20 to 40 lbs, about $3 to $5 per session |
| Stock tank with ice | 100-gallon tank outside, ice or cold weather | Tank plus ice; a wood-clad build was documented at about $400 (Functional Decor) |
| Tank with pump, filter and chiller | Chiller holds a set temperature, filter keeps water cleaner | One documented build with a 100-gallon tub, pump, chiller, filter, insulation and cover came in under $500; parts kits sell for about $416 without tank and chiller |
| Finished cedar plunge tub | Ready-made tub, add ice or a chiller later | From $2,554.50 (Baltic) |
Cost figures are from the sources named in the table, as published: HomePlunge, Functional Decor, the Plunge Crafters parts kit and a DIY build video by Rick Lohre. Prices change, so check before you buy.
What you need for a DIY cold plunge
- A tub deep enough to submerge your body from the neck down. Lowe's suggests a 100-gallon stock tank.
- A solid, level base, such as a concrete slab or concrete tiles on the lawn. Water is heavy: about 8.3 pounds per gallon, so 100 gallons weigh over 800 pounds before you get in.
- A hose to fill it, and ice to chill it.
- A floating pool thermometer, so you know the real water temperature.
- A non-slip mat for the tub floor.
- A cover, to keep out leaves and slow warming.
Source for the basic list: Lowe's, "How to Create a DIY Cold Plunge Tub".
How to build a stock-tank cold plunge, step by step
- Pick the spot. Level, solid ground, some shade, and close enough to a hose. Plan where the water goes when you drain it.
- Prepare the base. A concrete slab or pavers. Check that the surface can carry the filled weight.
- Set the tank and add a non-slip mat.
- Fill with cold water and add ice until the floating thermometer shows the temperature you want. See our cold plunge temperature chart.
- Cover it between sessions. Many DIY builders also insulate the sides with foam boards or a wood surround to slow warming.
- Change the water regularly, because an ice-only tub has no filter.
Adding a chiller, pump and filter
A chiller cools and circulates the water and holds a set temperature, so you stop buying ice. Usually a pump and filter come with it. This is where a DIY build gets technical: hoses, fittings, a power supply near water, and a filter routine.
- Use only equipment made for this purpose, and follow the chiller maker's instructions.
- Electricity and water need care: have a licensed electrician provide a GFCI-protected outdoor outlet.
- Chest-freezer conversions are popular online. We do not recommend them, because a freezer is not built to hold water you sit in.
For the trade-offs between ice and a chiller, read cold plunge with chiller or ice.
Safety first
Lowe's notes that cold plunging is not recommended for everyone and lists risks such as hypothermia, cardiovascular stress and hyperventilation. So check with your doctor before you start, keep sessions short, never plunge alone, and keep children and pets away from an open tub. We do not make health claims about cold plunging.
DIY or a finished cold plunge tub?
| DIY tank | Finished cedar tub | |
|---|---|---|
| Price | Low with ice; rises with a chiller and parts | From $2,554.50, chiller optional |
| Look | Metal or plastic tank, unless you clad it | Solid Eastern White Cedar |
| Setup | You source, assemble and maintain every part | The Baltic ships fully assembled |
| Warranty | Parts only, if any | 5-year residential limited manufacturer warranty |
A DIY tank is a good way to find out whether you like cold water. If it becomes a habit, a finished tub saves the tinkering. Our cedar tubs, made in Canada by Dundalk LeisureCraft:
- Baltic Plunge Tub: upright cedar barrel, 132 US gallons, ships fully assembled, $2,554.50
- Polar Plunge Tub: long tub to lie back in, 190 US gallons, $3,444 or $6,428 with a stainless liner
- Flow Cold Plunge: stainless tub with a hidden chiller compartment, from $7,850, chiller sold separately
Compare them in Baltic vs Polar vs Flow.
DIY cold plunge: FAQ
What is the cheapest way to cold plunge at home?
Your bathtub with cold water and ice. You only pay for the ice, though most bathtubs are too short to cover your shoulders.
What size tub do I need for a DIY cold plunge?
Deep enough to sit with water up to your neck. Lowe's suggests a 100-gallon stock tank.
How much ice does a cold plunge need?
It depends on the tub size, the tap water temperature and the weather. Add ice gradually and check the floating thermometer until you reach your target.
How do I keep a DIY cold plunge clean?
Cover it, rinse off before you get in, and change the water regularly. With a chiller, follow the filter routine in the manual. See cold plunge tub care.
Can I use a DIY cold plunge in winter?
Frozen water can damage a tank, fittings and chiller lines. Either follow the chiller maker's cold-weather instructions or drain the tub before the first hard freeze.
Ready for a finished tub?
Browse the cold plunge collection, read what is a cold plunge, or call +1 (307) 309-8328.