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Compression-fitted jets

Each jet body should be clamped to the shell by a gasket and a back nut, so a cracked one is unscrewed, not cut out.

Updated By the HotTubFinder research desk

Three ways a jet body is held in the shell: threaded with a gasket and back nut that unscrews (good), pushed into a rubber grommet (OK), or glued in and cut out to replace (avoid)
Top: a body held by a gasket and a back nut, which unscrews. Middle: pushed into a rubber grommet. Bottom: glued in, so it has to be cut out.

What it is

A jet has two parts. The insert is the face you see and twist out. The body is the housing behind it, set into a hole in the acrylic shell, with the plumbing glued or barbed onto its back.

A compression-fitted body is held like a bolt through a board. A flange sits on the water side, a rubber gasket presses against the shell, and a nut threads on from behind and squeezes it all tight. Undo the nut and the body comes out. Waterway, which makes jets for many brands, ships its Storm jet bodies with a gasket and a nut.

Why it matters

Jet bodies are plastic, and the shell around them flexes and heats up every day. Over the years a gasket hardens, or a freeze or a hard knock cracks a body. Water starts weeping out behind the shell, into the foam where nobody sees it, until the ground is wet or the water level keeps dropping.

On a compression-fitted body that's a small job. The tech digs out the foam behind that one jet, backs off the nut and fits a new gasket, or unscrews the body and threads a new one in. The parts cost a few dollars: Cal Spas' factory parts store lists a Power Storm body nut at $4.75.

If the body is glued into the shell, there's no nut to undo. It has to be cut or ground out and the hole cleaned up before a new body goes in, with a real chance of cracking the shell around it. That turns a cheap repair into hours of labor on the one part of the tub you can't swap.

How makers do it

Threaded body, gasket and back nut

The good way

The body's flange sits on the water side, a rubber gasket seals against the shell, and a nut on the back squeezes them tight.

Push-in body in a rubber grommet

Acceptable

A rubber ring fits the shell hole and the body presses into it. CMP's SQR jets and Jacuzzi's 2025-and-later jet backs work this way.

Jet body glued into the shell

Avoid

A serviceable body clamps the shell between a threaded fitting and a nut. A glued one must be cut out if it cracks.

In the showroom

  1. Ask the dealer how a cracked jet body comes out: unscrewed from behind, or cut out of the shell?
  2. Read the manual's parts list for jet body nuts and gaskets. Those parts mean a clamped body.
  3. At the parts counter, ask to see a jet body. Threads and a big ring nut mean a clamped body.

Ask the dealer

  • If a jet body cracks in year seven, is it unscrewed and replaced, or cut out of the shell?
  • Are these jet bodies held by a back nut, pressed into a rubber grommet, or glued?
  • Who sells the body nut and gasket for this tub's jets, and what do they cost?
Get the price range, then one dealer near you

The details

Where the evidence gets complicated, how each brand does it, and the sources.

Where it gets complicated

Nut-held isn't automatically easy: the nut sits under foam, and an old body can break coming out. Push-in grommet bodies sit in between. No maker explains its body mounting, so these grades rest on parts catalogues. The twist-out insert is a separate part.

Where the brands stand

15 of 15 brands

15 of 15 brands publish enough to tell. Where a brand doesn't, ask the dealer.

YesCal SpasJet bodies bolt in with a nut and gasket, per the factory parts store.YesMaster SpasJet bodies are held by a gasket and a back nut, so a leaking one is resealed, not cut out.YesWellisJet bodies bolt in with a nut and gasket, per Wellis's own parts store.PartlyAmerican WhirlpoolSome jet bodies bolt in with a nut; newer ones may press into a grommet.PartlyArtesian SpasSome jet bodies come with a nut and gasket; most aren't documented.PartlyBullfrog SpasShell jets bolt in with a nut; jets inside JetPaks aren't documented.PartlyCaldera SpasOlder jets bolt in with a nut; current jet bodies aren't documented.PartlyDimension One SpasLikely nut-held standard bodies, but Dimension One doesn't say.PartlyHot SpringMost jet bodies clamp the shell with a threaded ring; the newest aren't documented.PartlyJacuzziNut-held jet bodies through 2024; newer tubs switch to push-in grommets.PartlyMarquisOlder jets bolt in with a nut; current jet bodies aren't documented.PartlyNordic Hot TubsMost jet bodies bolt in with a nut and gasket; Nordic doesn't say.PartlyPDC SpasMost jet bodies come with a nut and gasket, per a PDC dealer's store.PartlySundance SpasMany jet bodies bolt in with a nut; the main Fluidix body isn't documented.PartlyVita SpaOlder jet bodies bolt in with a nut; newer ones press into a grommet.

Sources

10
  1. Waterway Plastics - Storm jet body assembliesWaterway's thread-in Cluster, Mini, Poly and Power Storm bodies each ship with a Kraton L-gasket and a nut.
  2. CMP - SQR systemTraditional jets seal by compression with nuts, gaskets and compression rings; SQR bodies press into a grommet that seals by radial force, with no nut or sealant. CMP says 30 spa makers use it.
  3. US Patent 5,850,640 - Hydrotherapy jet and fixtures for spa tubs and poolsDescribes the standard fixture: a wall fitting and gasket in the shell hole, with the jet body threaded on from behind and sealed, and a grommet-style alternative.
  4. Hot Tub Outpost - Jet wall fittingsWall fittings are threaded to fit a set hole size in the shell and are sold with or without a mounting nut and gasket, for about $5 to $15.
  5. Quick Spa Parts (Cal Spas factory store) - Power Storm jet nut PLU21800402Genuine Cal Spas part, $4.75; the nut secures the jet in place.
  6. Backyard Plus - Hot Spring fixed hydrotherapy jet partsHot Spring wall-fitting nut that screws into the jet body with the shell sandwiched between, plus a spanner wrench for the ring.
  7. Jacuzzi Hot Tubs - 2026 parts catalog, volume on jets (10976)Jet backs through 2024 listed with O-ring and nut; 2025 and later jets listed as grommet-style backs with a separate rubber grommet.
  8. Wellis parts store - 3-inch V3 jet body set (AJ00228SET)Wellis's own store sells the jet housing as a set with a self-adjusting nut and housing gasket.
  9. Master Spa Parts - search for SQR partsAn independent Master Spas parts store lists a 500 Series SQR jet body, the push-in grommet type.
  10. For A-Bodies Only forum - Hot tub plumbing threadOwner accounts: a nut-held body is a hollow bolt in a gasket, reached by removing foam; a glued body has to be ground or chipped out without cracking the shell. Read via search excerpt only.

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