Hot Tub Diverter Valves Explained: 1-Inch vs 2-Inch

Posted by The Spa Guy

Diverter valves are one of the most misunderstood parts in a hot tub.

Most people order the wrong one because they measure the cap — not the plumbing.

Let’s clear it up.

What 1-Inch and 2-Inch Actually Mean

The size of a diverter valve does not refer to:

• The size of the cap
• The size of the handle
• The outside diameter of the top

It refers to the plumbing that glues into the body of the valve.

1-inch diverter = 1-inch pipe glues into it
2-inch diverter = 2-inch pipe glues into it

That’s the deciding factor.

How to Measure the Threads

If you’re replacing just the cap or handle, you need to measure across the threads.

Typical measurements:

1-inch diverter → approx. 1 5/8 inches across threads
2-inch diverter → approx. 2 3/4 inches across threads

Now here’s the confusing part:

The outer cap width on a 2-inch valve can range from 3 1/4 inches up to 5 inches depending on the style.

The thread diameter is what determines compatibility.

Always match thread width first.

What Does a Diverter Valve Do?

A diverter controls water pressure distribution inside your spa.

Common uses:

1-inch diverters → neck jets or waterfall controls
2-inch diverters → foot jets or large jet clusters

Turn left → sends power to one jet group
Turn right → sends power to another
Middle position → splits flow between both

It increases pressure by focusing water where you want it.

Major Manufacturers (And Why They Interchange)

Most modern diverter designs originated from:

HydroAir
Waterway
CMP

They copied each other’s thread designs over the years.

That means many 1-inch and 2-inch diverters will interchange — as long as the thread width matches.

Some spa brands customize the look, but not the thread design.

Buttress vs Standard Threads (2-Inch Only)

On 2-inch diverters, you may see:

Buttress threads
Standard (non-buttress) threads

Most of the time they will interchange.

But here’s the rule:

If your cap says “Buttress” underneath, stick with buttress.
If it does not, order standard threads.

Common Diverter Failures

Over time diverters can fail because:

• Threads crack
• Caps break
• O-rings flatten or dry out
• The valve body pulls downward under the shell

That last one is important.

As spas age, plumbing stiffens and shells flex slightly. The diverter body can get pulled down into the cabinet, leaving fewer threads exposed.

That can cause:

• Caps that won’t tighten
• Caps that pop off
• Water leaks

In some cases, the cabinet must be opened and the valve repositioned or replaced.

Can You Upgrade the Look?

Yes.

You do not have to replace it with the exact same style.

Newer six-spoke caps and larger grip styles often fit older diverters — as long as thread diameter matches.

Just make sure:

• You verify thread width
• You check for buttress vs standard
• You have enough clearance for larger caps

Some 2-inch caps are nearly 5 inches across.

Special Note on Jacuzzi® Premium Models

Some Jacuzzi® systems use diverters that measure around 3 7/8 inches across the threads.

They function like 2-inch diverters but use proprietary sizing.

Always measure before ordering.

Why Buy From HotTubPartsOfAmerica?

We stock:

• 1-inch diverters
• 2-inch diverters
• Caps only
• Handles only
• Complete valve assemblies

Not sure what you have?

Text us clear photos.

Send:

• A top view
• A side view of threads
• Any markings underneath

We’ll confirm the correct replacement before you order.

? Text photos: 772-800-5445
☎️ Call: 844-500-4645
? HotTubPartsOfAmerica.com

Ordering the wrong diverter wastes time and money.
We make sure you get it right the first time.

— The Spa Guy

HotTubPartsOfAmerica.com

Important Disclaimer

HotTubPartsOfAmerica.com is not affiliated with, endorsed by, or connected to Jacuzzi®, Sundance®, Dimension One®, Watkins®, Hot Spring®, Tiger River®, Caldera®, or Solana®. All brand names are used strictly for compatibility and identification purposes.