Hot Tub Supply Spa Depot
Hot Tub Leaks
Diagnosis & Repair
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Hose Filter

Fixing spa leaks Hot tub leaks may seem hard to find, but it's not difficult if you know where to start. Look for water under your pump first, as a common cause is bad seals. Check around the heater, pressure switch, pipes, unions, and connections.

If you decide not to tear into the equipment, use of a quality leak sealer can save you some time and repair money. Although not always a permanent fix, they can be effective on many leaks, with the exception being bad pump seals, which will need to be replaced.

Components associated with spa leaking:

  • Pump Wet End Seal
  • Heater Assembly Manifold
  • Slice/Knife and Gate Valves
  • PVC Plumbing Parts & Tubing
  • Jet Bodies
  • Acrylic Spa Shell
  • Wooden Hot Tubs

Step-by-Step Repair Diagnostics

A) Disconnect all power to the spa. Inspect the equipment compartment. If leak is under the pump, this indicates a possible pump seal failure. If leak is detected, replace pump or install new seal, as appropriate.

B) Check all union fittings at hot tub pump and heater.  Unions can even vibrate loose on a brand new spa during shipment, and should be hand tightened if necessary.  If hand tightening is difficult, loosen pump mounting bolts, move components into alignment, then tighten unions and re-tighten pump mounting bolts.  Never use a wrench to tighten spa unions.

C) Next, inspect heater, pressure switch and surrounding components. Replace any defective parts as indicated by leak.  See Heater Testing

D) Inspect all of the valves. Repair or replace if leak is indicated. Knife style valves are sometimes bolted together and contain a gasket between the halves which can fail, particularly upon freezing or with prolonged poor water quality conditions.

Note: Valves on either side of the pump, when present, are installed at the factory as a convenience to service people (so that they do not have to drain the spa water to replace a pump).  In reality, these valves more often do more harm than good, since they are a common source of leaks.  Some hot tub owners choose to remove these valves if they have been a leak problem source.

E) Inspect all pipes, jets and connections for leakage. Repair or replace if indicated.

Repair PVC with PlastAid There is only one product that we have ever found that can reliably and permanently fix many leaky PVC components: Plast-Aid.  This product forms a molecular bond with the plastic which is stronger than the PVC pipe itself.  It is far superior to epoxy compounds.

Leak Detection

One method for locating leaks is to use dye (dark food color) in the water. This method works best if the leak is substantial. Observe location of dye leakage, using flashlight if needed, and proceed with repair.

Another method is to let the water drop (with spa not running) and then observe the water level of the spa when the level ceases to drop. If the water stops dropping at a jet for example, that jet is the likely leak source.

For faster leaks it may help to determine the type of leak: vessel leak (spa shell), suction-side leak (before pump) or pressure leak (after pump). Fill spa and mark the water level with grease pen or crayon, and allow the spa to run for 24 hours. Now mark the new water level to determine how much the water level has dropped. Refill to original mark, and keep system off for 24 hours. Again, note how far the water dropped. If the water dropped the same amount on both tests, this usually indicates a vessel leak (blisters and most surface cracks are usually only cosmetic, and not normally a cause for leaks). If the water dropped more with system running, this indicates a pressure leak. If the water dropped less with system running, this indicates a likely suction leak.

Fixing Leaky Pipe Connections the Easy Way

A common area of hot tub leaks occurs where PVC fittings (couplings, elbows, tees, etc.) connect to spa flex pipe. These repairs used to require cutting out the affected pipe, and replacing the PVC fittings. Our new Clip-on Pipe Leak Seals now make these repairs simple, inexpensive, and very effective. A repair job that previously took an hour or more, can now be completed in a few minutes at a fraction of the cost.

Repair PVC Clip-on Leak Seal Repair PVC snap-on Leak Seal

Simply clean and dry the affected area. Apply PVC primer to the Clip-on fitting. Then apply PVC cement to both surfaces, and snap in place while giving a quarter turn. These repair fittings are designed and sized to fit over the flex or rigid PVC pipe and fittings.

Clip-on Leak Seal for 1.5" Plumbing
Clip-on Leak Seal for 2.0" Plumbing
PVC Pro Cement Kit (this kit contains PVC cleaner, primer, and spa-grade cement)

Repairing Shell Cracks

Most so-called shell leaks are actually leaks associated with jets or other fittings, not the shell itself.  Today's hot tub shells are cast acrylic which has been vacuum formed and then reinforced on the underside with a thick layer of fiberglass.  It is extremely strong.  Even if the acrylic layer were to crack or blister, a water leak penetrating the fiberglass would be unusual.

Acrylic shell cracks and blister voids can be effectively filled and repaired with Plast-Aid.  This compound can even be colored with acrylic* artist paints (available at any art supply store) to approximate the original color of the spa shell.

*do not use oil based colorants

PlastAid repair compound

Plast-Aid is a two part product (filler and hardener) that can be formed, sanded, and polished, and is the only effective compound available for permanent acrylic shell repairs that we have found. Unlike epoxy or fiberglass repair products, Plast-Aid forms a molecular bond with the acrylic shell.

Jet Body - Vessel Leaks

Spa jet body gasket More often, a vessel leak can be traced to a bad jet or other shell fitting.  Jet bodies have a flexible gasket which is tightened against the underside surface of the spa shell.  These gaskets can sometimes shrink or decompose over time, resulting in water loss.  You may have to remove some of the shell's foam insulation to access these jet gaskets or other plastic fittings such as floor drains, suctions, etc.

Make sure the area is clean and smooth before installing a new component.  After installing and tightening a new jet body or other component, apply a generous layer of silicone sealant around the gasket perimeter and fiberglass undershell as an added measure of future leak protection.

Seal-A-Leak sealer

Minor leaks can often be stopped with Seal-a-Leak Spa Leak Sealer #MT1018.  

Plast Aid plastic repair compound

Acrylic spa surface cracks and PVC pipes can now be permanently mended with Plast-Aid #MT1044.  This product is particularly useful for hard to remove parts. Many other uses around the home, boat, and auto.  

Leaky Wooden Hot Tubs

Leaky wooden hot tubs There are still a few unlined wood tubs around, so we will touch on them briefly here.  First, it must be determined why the vessel is leaking.  If the tub has leaked since installation, then the cause is likely improper assembly.  Correction may require disassembly to find and fix the errors made when it was put together.  Refer to the installation manual and consult with the dealer for help if necessary.  Continue reading if disassembly is impractical.

Once a wooden tub has been used, it is important to keep it wet.  If the wood is allowed to dry-out, it will begin to shrink (much like an old wooden boat hull out of water) and this can cause gaps to open up.  Often, refilling it with water and allowing the wood to reabsorb moisture will cause the gaps to tighten, unless severe warping has occurred.

If the hot tub has held water without leaking for some time, and then begins to leak, the problem may be from wood degradation.  A common cause is the use or overuse of chlorine and bromine which results in delignification, a process in which the wood cells are actually eaten up.  A symptom is the presence of cellulose fuzz on the tub's surfaces, which can be removed with a stiff brush.

NOTE: After fixing your leak problem, consider switching to an alternative sanitizer such as Cleanwater Blue, which will not attack wood.

Other conditions which may cause leaks are sustained improper water balance (pH too high or too low), a shifting foundation due to ground settling, or insect infestation.  Carpenter ants, for example, seek out and devour wet wood.

Household sealants, which are usually solvent or silicone based products do not work well for this type of leak because they do not adhere to wet wood.  Some tout sawdust made into a paste, then forced into cracks to help to seal leaks.

Drain or vacuum any hot tub with the amazing Shake-a-Vac:

Spa Drain and Vac

Spa customers write  Consumer Reviews

"I inherited an older Jacuzzi Spa with our new home. It had a slow leak at the filter compartment hose that got a lot faster after I drained and refilled it. I could get the parts for repairs, but when I try these kinds of projects they usually GROW in size. I buy all my spa products from Spa Depot and saw Seal-a-Leak Spa Leak Sealer. It was inexpensive so I thought it was worth a try. I followed the label directions and used half the bottle, ran the spa overnight and in the morning the leak has stopped! The product is nothing short of a miracle."

Jason Jackson
Grass Valley, CA

"It's what I use for repairing leaks in PVC hot tub plumbing lines and even to fix worn-out threaded fittings. It bonds permanently to cracked acrylic spa shells and is the only reliable way to fix shell leaks I know of. Often there is no need to drain the spas and pools I work on. It's a product that makes many of my jobs a lot quicker. After trying Plastaid, I don't even keep epoxy in my toolkit anymore because there's no comparison!"

Bobby Wells
Spa Technician
Austin, TX

"It's what I used to fix my cell phone. It saved me over $100 bucks!"

Casey Winkleman
Portland, OR

Spa Depot, The, Spas & Hot Tubs - Dealers, Olympia, WA

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