Much of the challenge of fixing a leaky hot tub jet is finding exactly where the leak is. In some types of spas, this is easier than in others. In a spa that allows access from all sides of the spa and does not have the whole cabinet full of foam, the leak can be detected by putting down a piece of paper under the suspected spot, or just by observing where water is puddling. Once a leak has been fixed, it needs to be determined if the spa should be emptied or spa water level lowered to at least below the point of the leak to allow for repair.
In order to actually repair the leak once it is found, a few parts may be needed including PVC couplings, hose or pipe, jet backs or manifolds. Having the right plumbing parts on hand with a plan on what to cut out, glue and replace will make the process a lot easier.
A Stanley knife can be used to cut out a hose from a jet socket or otherwise prepare a hose for a coupling. If there is sufficient slack in the existing plumbing, sometimes a hose can just be reconnected, but with many hose connections tight, adding in a coupling and additional piece of hose may be needed.
For example, for a leak behind a jet that is on a 1/2 inch hose plumbing line (typically the hose diameters are smaller at the jet and larger before the manifold that divides up the main water supply to each jet line) the bad part of the hose needs to be cut out and the inside of the jet fitting cleaned of all residue. Then the hose is cut back and a new coupling (in this case 1/2 inch) is then glued onto the existing length of hose with PVC pipe glue.
The blue glue seems to work the best which is commonly found in pool and spa repair shops and online. It comes with an applicator/dabber right in the glue can. Before a joint is glued, PVC primer is used to clean the connection so the bond will be complete. After cleaning both parts to be connected with primer, the glue is rolled around the entire part a few times and then the parts are pressed together and held tight for a few seconds to allow it to bond. Fast drying PVC glue will help create the initial bond in a matter of seconds. Next, add the additional small piece of hose to the new coupling and finally prime and glue the assembly into the existing, cleaned out jet back for a permanent fix.
It is recommended to let the glue joints cure overnight and then refill the spa the next day to test. Sometimes secondary leaks may be found at the same time.
Fixing a leaky spa jet once the jet is actually found is a matter of having the rignt PVC parts, hose, pipe,primer and glue on hand to complete the job.
Good luck with your hot tub plumbing repair!
When in doubt, there are always qualified hot tub repair technicians standing by to complete such a repair for you.