Shower Valve

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Shower Valve

Have you ever been taking a shower when the water from the showerhead suddenly becomes scalding hot or icy cold? That sudden temperature change is due to a drop in either the hot or cold side water pressure. This can happen when someone else in the house turns on the water at a fixture, when the washing machine fills, when a toilet flushes, or even when the dishwasher begins a cycle that uses water. Sometimes the situation is just startling and annoying, but a sudden blast of hot water can also create scalding burns.  Your shower valve has a lot to do with this.

A pressure-balance shower valve or thermostatic shower valve can remedy these hot/cold balance issues.  In California, building code requires one or the other for new construction and remodeling.

Do not spend thousands of dollars remodeling your shower or bathtub and install the wrong valve!  Moreover, don’t be mislead into thinking replacing the shower valve will fix a problem it can’t.  If you have any questions about this, call or email me at (949) 380-0177 or

Does a Shower Valve Really Matter?

Yes!  Many folks when they remodel their shower simply know they are getting a new shower.  Because their professional expertise and experience is not in bathroom remodeling, they do not know there is a difference.  A shower valve is a shower valve – right?  They are all the same – aren’t they?

Shower Valve
PB Valve

Shower Valve
TS Valve

Transfer Valve
TV / DV Valve

Shower Valve
MV Valve

There are four types of shower valves:

  • Pressure-balance (PB) shower valve – $100
  • Thermostatic (TS) shower valve – $300
  • Transfer (TV) or Diverter (DV) shower valve – $200
  • Mixet (MV) shower valve – $20 for replacement cartridge

The illustrated price represents an average retail price to purchase.  Installation, trims, and accessories are an added cost.

Each of these shower valves have a different function.  Valve design and operation is constantly evolving.  Every manufacturers valve looks and performs differently.

Below are pictures of what a typical shower might look like with a particular shower valve.  There are many potential configurations.  These are the ones I tend to see in Orange County.  Let’s take a look at these shower valves and see which one is best for your bathing experience.

Shower Valve
PB Valve

Shower Valve
TS Valve with TV

Shower Valve
TS Valve with TV

Shower Valve
Mixing or Mixet Valve

Shower Valve Environmental Factors

There are many factors impacting shower valve performance.  Even the best shower valve cannot compensate for poor environmental factors.  For shower valves, these environmental factors are water pressure, volume, and temperature.  These three items will determine the performance of any shower valve.

The primary purpose of a shower valve is to regulate both the volume and pressure of water going through the shower head and the temperature.  Volume and pressure are functions of the homes (in this order):

  • Water Pressure Regulator

    Water pressure into the house.

  • Hot and cold-water pipe sizes throughout the house.
  • Configuration of the home water pipes when installed.
  • How many water appliances are being used at the same time.
  • Age, condition, and maintenance of the shower valve.

Temperature is a function of all the items listed above plus:

  • Size, age, type, and location of the water heater.
  • Where the water pipes are installed (ground, attic, etc.).
  • How the shower hot and cold-water pipes were configured when installed.
  • Condition of the water pipes.
  • Are the hot and cold-water pipes insulated?

Shower Valve Types

While they are often confused, there are actually two types of shower valves that can serve to balance water temperature and prevent burns.  These are PB and TS valves.

Pressure Balance (PB) Shower Valve

Pressure Balance Shower Valve
Kohler Pressure/Balance Valve
Pressure/Balance Shower Valve
Kohler PB Valve Disassembled

A pressure balance valve has a single control that regulates the ratio of hot to cold water that flows out of the fixture.  There is no true volume control with a PB valve.  When the valve is turned on, 100% water volume passes through.  The more the valve is opened, the hotter the temperature gets.  Pressure balance valves have a maximum temperature limit that is set at the time of installation, which provides scald protection for families with children.  The temperature stop is usually set not to exceed 120ºF.  This can be adjusted.

The most common scenario that people think about is how the shower reacts when a toilet is flushed.  The tank of the toilet will need more cold water to refill after the flush, so there will be less cold water for the shower.  In this scenario, the PB valve automatically reduces the amount of hot water as it senses this.  The pressure remains constant and so does the temperature.

Shower ValveHow a Pressure-Balance Valve Works

A pressure-balance shower valve works by maintaining a balanced flow of water between the hot and cold side. They do not actually sense the temperature of the water. The valve has either a balancing spool or a diaphragm inside the valve body that reacts to drops in the pressure of one incoming water supply (either hot or cold) and adjusts the outflow of the opposite water supply to match. This ensures that the water doesn’t get suddenly colder or hotter as it emerges from the spout of the showerhead. Sudden changes in supply water pressure may reduce the outflow of water from the showerhead, but it will not change the temperature.

Thermostatic (TS) Shower Valve

Thermostatic Shower Valve
Kohler Thermostatic Valve

Thermostatic Valves have two control valves.  One controls the pressure, and one controls the temperature.  TS valves also provide maximum temperature limits that provide scald protection.  These valves allow the user to set the temperature completely independent of the volume.

The water temperature remains the same, no matter if the water is trickling or running full blast.  This type controls the temperature to within one degree of whatever setting you establish with the temperature control. The chosen temperature will remain at the same setting after you turn the water off, so the next shower will automatically be set exactly where you left it.  Thermostatic shower valves are regarded as far superior to pressure-balance valves, but they are also more expensive.

Today, many TS valves act as both a TS and TV.  Therefore, it is possible to have a single TS valve performing the work of 2-3 TVs.  This removes “shower wall fixtures clutter”, creating a less busy shower.

TS valves make it easy to find the correct temperature every time.  Thermostatic valves also allow the user to control the volume.  Therefore, you can enjoy a very hot temperature at low volume.  The opposite is also true.  PB valves do not have that capability.

How a Thermostatic Shower Valve Works

Kohler Thermostatic Shower Valve AssemblyThermostatic shower valves use a more sophisticated mechanism.  It actually senses the temperature of the water rather than merely reacting to the volume of flow between hot and cold inputs. A wax element inside the shower valve expands or contracts in reaction to heat.  This changes the amount of water allowed in from each inlet. While this might sound virtually the same as the less expensive pressure-balance valve, there are key advantages:

  • The temperature remains the same no matter what volume you set. This makes water conservation easier.
  • You can set the water heater at a high-temperature setting.  However, the shower valve itself can be limited so that the water temperature never reaches a scalding level. This allows washing machines, dishwashers, etc., to use much hotter water than you want in a shower or bathtub.
  • With these shower valves, you generally set the water temperature and water volume with separate controls.

Mixing or “Mixet” (MV) Shower Valve

A “mix-it” valve is not a PB valve.  Many people confuse the two.  A “mix-it” or “mixing” valve is designed to draw water to the shower head from the hot and cold taps (pipes). Mixing valves are primarily found in older houses.  

Mixing or Mixet Shower Valve
Mix-It Valve

Mixing valves cannot regulate sudden changes in water pressure.  The risk of getting scalded if a sink, toilet, or washer unexpectedly draws cold water is high with mixing valves.

The Mixet Company manufactured the Mixet valve.  The Mixet company is no longer in business, but thousands of their shower valves are still in operation. When repairs are needed, it is a fairly easy and inexpensive job to replace the internal cartridge with one offered by an aftermarket manufacturer, designed to match the original part.  When you decide to remodel your shower, make sure to replace with a PB or TS valve.  Mixing valves are dangerous and can cause serious burns – especially to children.  Mixing valves are no longer permitted in new construction or remodeling.

Shower Diverter/Transfer Valve

These are not shower valves in the traditional sense.  Used in showers and bathtubs, they serve a different purpose.

Transfer or Diverter Valve (TV or DV)

Transfer Shower Valve
Kohler Transfer Valve

Used in showers, tubs, and tub/shower combinations.  Transfer valves direct water to shower or bathtub components.  There are three types of shower transfer valves.

  1. A tee diverter consists of a pull arm on a tap, usually the bathtub faucet.  When the water reaches desired temperature, the user pulls the arm to block the tap and the diverter valve directs the flow to the shower.
  2. A two-valve diverter uses a rotating control for hot and cold.  It has a second control to divert water between the tub or the various shower components.
  3. A three-valve diverter allows individual adjustments of cold and hot water.  Plus, a central knob to divert water between the tub and the various shower components.

There are also shower only transfer valves.  Kohler’s Master Shower transfer valve brings a new level of innovation and flexibility as a custom shower solution.  When paired with compatible trim, its three-way design allows control of up to three separate components.  It easily configures to a two-way transfer valve.  This unique feature allows one valve to control all functions from a single valve.  This greatly reduces “shower wall clutter”.  This makes for a very aesthetically appealing shower with multifunction capabilities.

Does the quality of a Shower Valve Matter?

 More than you can possibly imagine!  When considering shower valves, here is what matters:

  • Manufacturer
  • Warranty
  • Cartridge

Kohler Pressure Balance Shower Valve
Kohler PB Valve $100

Kohler RiteTemp Cartridge
Kohler PB Cartridge $30

Delta Pressure Balance Shower Valve
Delta PB Valve $38

Delta Pressure Balance Cartridge
Delta PB Cartridge $36

Looking at the above table, there are two manufacturers – Kohler and Delta.  Retail, specialty, and internet stores carry their products.  Both offer lifetime warranties and have solid brass valves.  So, what is the difference besides the obvious price?  Here is where experience becomes critical.  Experience only a professional Plumber or Contractor like DAD’s Construction can provide.

Most folks will look at the above and go with the lower price.  That would be a huge mistake.  Kohler has the lowest overall cost of ownership by a wide margin.  Here is why.


Kohler PB valves are forged using dezincification-resistant brass bodies that provide long term reliability and resistance to aggressive water conditions.  This entire sentence screams “perfect” for the water we have here in Orange County.  I have never had a Kohler fixture fail in 45 years.  I can’t say that for other manufacturers.


  1. Kohler – “Kohler Co. warrants its faucets to be leak and drip free during normal residential usage for as long as the original consumer owns their home. If the faucet should leak or drip during normal usage, Kohler Co. will, free of charge, mail the cartridge necessary to put the faucet in working condition.”
  2. Delta – “All parts and finishes of the Delta faucet are warranted to the original consumer purchaser to be free from defects in material and workmanship for as long as the original consumer purchaser owns their home. Delta Faucet Company recommends using a professional plumber for all installation and repair.”

The Kohler warranty says it.  If something goes wrong, they will mail you the part free of charge.  It also does not recommend using a professional plumber at up to $100+ per hour.


Kohler designed cartridges are easy to replace.  You don’t need a professional plumber at up to $100+ per hour.  From my personal experience, Kohler cartridges will outlast competitors by a wide margin.  Replacing less often means lower overall cost.  Look at the two cartridge pictures.  The Kohler is obviously superior to the Delta.   Kohler cartridges are seize resistant in aggressive water conditions and made with premium materials for enhanced durability.  They are a superior cartridge at a lower price than the Delta (and many others).

When Does a PB or TS Valve Cartridge Require Replacing?

Pressure Balance Valve:

Kohler RiteTemp CartridgeLike older standard shower valves, pressure-balance shower valves have inner cartridges that wear out and eventually go bad. When it does, the cartridge may not mix the water evenly and you might get mostly hot or mostly cold water. Or you may also get barely any water at all. These are all signs that you need to change out the cartridge.

Replace the cartridge and it should work like new. You can extend the life of the shower valve by turning it on regularly, even if that bathroom does not get any use.  A regularly used shower valve is less likely to go bad.

Thermostatic Valve:

Kohler Thermostatic CartridgeThermostatic shower valves also have cartridges that wear out and need replacement.  They are also susceptible to problems originating with dirt or debris in the check valves that control the flow of water from the hot and cold inlets. If your thermostatic shower valve suddenly stops controlling the water temperature or water volume correctly, the first step is to inspect and clear the check valves, following the manufacturer’s directions. If this doesn’t solve the problem, then replace the cartridge.

Note: When installing a new pressure-balanced or thermostatic shower valve, save the paperwork.  It will make it easier to identify which replacement cartridge you need when the time comes to change it. Sometimes a quick call to the manufacturer can result in a free new cartridge, so keep the phone number handy.

Can I extend the Life of my Cartridge and Shower Valve?

ScaleBlaster Home Water Filter SystemYes!  My professional recommendation is to install a ScaleBlaster when you remodel your shower, tub, or kitchen.  ScaleBlaster is also a “must have” when you replace your water heater or re-pipe your home.

ScaleBlaster is an electronic water conditioner that’s affordable, eco-friendly, salt-free, chemical-free and a maintenance free solution to your limescale deposits and soap scum.  It’s completely safe for both the environment and your family.

To learn more about this truly innovative and outstanding product, please see ScaleBlaster.

Always Hire a Reliable and Dependable Contractor to Remodel your Bathroom

Design Build Bathroom Remodel | Best Local Contractor DAD's ConstructionAlways work with a trustworthy contractor like DAD’s Construction.  We are experts in bathroom remodeling who can manage projects in an efficient manner.  DAD’s Construction will do everything to minimize the possibility of change orders.  Our team will make sure we have all the necessary information to prepare a proposal that meets your requirements.  Rest assured that we will provide you with a detailed, by line-item contract.  We will make sure that the contents of this agreement are properly and clearly communicated to you.  If you have questions or need updates regarding your project, we will always answer your inquiries.

How Can I Receive More Information?

If you would like more information on enjoying the best bathroom, kitchen, and interior remodeling experience in Orange County, call Dan at (949) 380-0177 or at for a free in home consultation.  DAD’s serves all of South Orange County California.  This includes Lake Forest, Mission Viejo, Foothill Ranch, Portola Hills, Ladera Ranch, Irvine, San Clemente, Dana Point, San Juan Capistrano, Rancho Santa Margarita, Coto de Caza, Dove Canyon, Laguna Niguel, Laguna Hills, Newport Beach, and Aliso Viejo.

Best Local Shower Contractor | DAD's Construction

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Daniel A. Derkum is the owner of DAD’s Construction, a leading South Orange County, California design-and-build remodeling and renovation Contractor,  © DAD’s Home Services & Construction, Inc.  All Rights Reserved.