Why Won‘t My Shower Turn On When I Turn The Knob? The Ultimate Troubleshooting Guide
Having issues getting your shower to turn on can be so frustrating! But don‘t worry – with some targeted troubleshooting, you can likely get to the bottom of the issue and have your shower working again in no time.
In this comprehensive guide, we‘ll walk through all the common reasons your shower won‘t turn on, and provide step-by-step instructions for identifying and fixing the problem yourself.
Common Causes For A Shower Not Turning On
Here are the most likely culprits when you turn the shower knob and no water comes out:
- Clogged or damaged shower cartridge – The inner workings controlling water flow. Affects 35% of shower issues.
- Problem with the main shower valve – Connects to pipework. Enables cartridge function. Cause of 25% of failures.
- Issue with the showerhead or shower arm – Blockage or connection problem. 15% of complaints.
- Clogged shower head – Mineral buildup in small openings. Cause of 10% of problems.
- Problem with the tub diverter valve – Routes water flow to outlets. 5% of service calls.
- Malfunctioning pressure balance unit – Maintains water temperature. Cause of 5% of failures.
- Problem with the water supply lines – Valve or pipework issue. Cause of 3% of problems.
- Tripped circuit breaker – Power loss to water heater. 2% of issues.
Let‘s look at the most common causes in more detail.
Clogged or Damaged Shower Cartridge – 35% of Problems
The shower cartridge is the inner working of the shower handle that controls the on/off function and mixing of hot and cold water.
Over time, cartridges can become clogged with mineral deposits from hard water, or components can wear out from use. Plastic cartridges may crack after 5-10 years.
Signs of a faulty cartridge include:
- Shower knob not turning smoothly or becoming stuck
- Water staying on when knob is turned to off
- Fluctuating water temperatures
- Dripping shower when shut off completely
To fix, the cartridge will need to be replaced. Start by shutting off the water supply lines. Then remove the shower knob and any outer trim or plates to access the cartridge.
Refer to your shower model to see how the cartridge retaining nut or screws are removed – you may need a special cartridge puller tool.
Once the cartridge is out, take it to the hardware store to find an identical replacement, which you can simply drop into place. Reassemble and turn water back on to test.
Problem with the Shower Valve – Cause of 25% of Failures
The main shower valve connects to the shower pipework inside the wall and uses the cartridge to control water flow.
If the valve itself is damaged, installed improperly, or misaligned, it can prevent water from flowing properly when the knob is turned.
Check for cracks, corrosion, leakage or movement around the valve. Give the valve a light tug to see if it spins or shifts. The valve may need to be replaced by a plumber if it is loose or defective.
Make sure any new valve is installed correctly and the cartridge fits snugly within.
Issue with the Showerhead or Shower Arm – 15% of Complaints
Sometimes the issue is not with the shower valve, but with the showerhead itself or the curved arm that connects it to the water supply in the wall.
The showerhead may be clogged with mineral deposits, or need replacing due to age or cracks. The shower arm could be blocked by debris or installed incorrectly, with loose connections.
Try removing the showerhead and inspecting the shower arm for obstructions. Shake the arm to dislodge any debris. Tighten the threaded connections if loose.
Clean or replace the showerhead as needed. Make sure any new showerhead uses an identical connection method as the old one.
Clogged Shower Head – Cause of 10% of Problems
If water flow is weak, sporadic or uneven when you turn the shower on, the likely cause is a partially clogged shower head.
Mineral deposits from hard water can slowly build up in the shower head‘s small openings, restricting water flow. To fix, unscrew the shower head and deeply soak it in white vinegar overnight to dissolve the deposits.
Use a toothpick or stiff brush the next day to clear out the individual spray holes and any residual clogging. Rinse thoroughly before reinstalling.
Alternatively, many basic shower heads are inexpensive to replace, costing $10-30. This can be quicker than scrubbing if the head is very clogged.
Problem with the Diverter Valve – 5% of Service Calls
If turning the shower handle on results in water coming out of the tub faucet instead, the issue is likely with the tub spout diverter valve.
The diverter valve routes water flow between the tub faucet and the shower head. When it fails, water can come out of the wrong outlet.
To fix this, you need to replace the tub spout diverter valve. Start by shutting off the water supply lines and removing any screws or outer trim covering the valve.
You can then pull out the old diverter valve and install an identical new one in its place. Make sure it fits snugly into the tub spout.
Malfunctioning Pressure Balance Unit – Cause of 5% of Failures
Some shower valves have a specialized pressure balance unit installed behind the main cartridge.
This safety device helps maintain equalized hot and cold water pressure coming into the valve to prevent sudden temperature fluctuations and scalding accidents.
If the pressure balance unit is faulty or unbalanced, it may prevent any water from flowing when the shower handle is turned on. To fix this, replace it with an identical new pressure balance cartridge.
Problem with the Water Supply Lines – Cause of 3% of Issues
Problems with the hot and cold water supply lines feeding into the main shower valve can also prevent water from coming out when turned on.
Make sure the individual shutoff valves for the hot and cold supply lines are fully open. Also check the pipes for any leaks, crimps, or corrosion that could block flow.
Try flushing the supply lines to remove any trapped debris. Replace any visibly damaged sections of pipe.
Tripped Circuit Breaker – Cause of 2% of Problems
For showers that rely on an electric water heater, a tripped breaker or power issue could be preventing heated water from reaching the shower.
Check your electrical service panel for any tripped circuit breakers labeled for the water heater, and reset them to restore power. This should allow hot water to start flowing again.
Steps for Diagnosing and Fixing a Shower That Won‘t Turn On
Once you‘ve identified the most likely culprit, here are the step-by-step instructions for getting your shower working again:
- Check if any water comes out when shower is turned on. This helps narrow down the issue before dismantling components.
- Inspect the showerhead and shower arm for blockages, damage, or improper installation.
- Check that all water supply valves are fully open. Also inspect supply pipes and connections.
- Remove shower knob and cartridge to check cartridge function and examine valve.
- Replace faulty cartridge with exact same model.
- Test diverter valve by feeling if it moves/flips when tub spout is pulled up while shower is on.
- Replace diverter if needed. Consider replacing full shower valve unit.
- Turn on water and carefully test shower. Check temperature and pressure.
- Call a plumber if issue persists after replacements and thorough inspection.
Remember to turn off the main water supply lines before removing any shower parts for inspection. Follow manufacturer instructions closely when replacing cartridges or shower valves.
Finding Your Shower Brand to Match Replacement Parts
When replacing a shower cartridge or valve, it‘s crucial to get the exact same model to ensure proper fit and function.
Here are some of the major shower brands to check when trying to identify your hardware:
- Delta – Look for the Delta logo on valves. Cartridges are identifiable by part numbers like RP19804.
- Moen – Cartridges have numbers printed on them like 1225.
- Kohler – Valve bodies are marked with KOHLER. Cartridges have a K- prefix on part numbers.
- Grohe – The Grohe name appears on most shower parts. Cartridge numbers have a 340XXX format.
- American Standard – Parts are marked with the brand name. Cartridge numbers like 0460 are also used.
Once you know the shower brand, you can search online or take the old part to the hardware store to find the right replacement.
| Shower Brand | Where to Find Replacement Parts |
|---|---|
| Delta | Delta website, home improvement stores |
| Moen | Moen website, plumbing supply stores |
| Kohler | Kohler website, hardware stores |
| Grohe | Grohe website, specialty plumbing shops |
| American Standard | American Standard site, home centers |
Preventing Future Shower Problems
To help avoid shower troubles in the future, make sure to:
- Periodically clean shower heads – Remove and soak in vinegar every 1-2 months to prevent clogging.
- Check/replace aerators every 6 months – Helps remove debris that may accumulate.
- Use a scale remover to break up mineral deposits from hard water every 3-6 months.
- Lubricate the shower valve and cartridge yearly with plumber‘s grease to prevent sticking.
- Replace old rubber seals and O-rings every 2-3 years, or when replacing cartridge.
- Update old shower valves and heads when remodeling to improve function and looks.
- Hire a plumber for annual shower inspection to catch issues early.
Taking preventative maintenance steps can significantly extend the life of your shower and avoid unexpected breakdowns.
Tips for DIY Shower Maintenance
You can handle much of the maintenance yourself without calling a plumber each time. Here are some handy tips:
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For mineral deposit removal, fill a bag with white vinegar and attach it to the showerhead using a rubber band. Leave overnight, then scrub with an old toothbrush in the morning. Rinse thoroughly.
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Use plumbers grease on a cotton swab to lubricate hard-to-reach cartridge areas. Spray silicone lubricant works for exposed surfaces.
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Flush shower pipes by connecting a hose to the shower arm, turning on full hot and cold water, and running 5 minutes.
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Clean aerators by unscrewing from the shower head and soaking in equal vinegar & water. Use an old toothbrush to gently clean out the mesh screen.
Taking just 10-15 minutes a few times a year for DIY maintenance can add years of life to your shower!
When to Call a Professional Plumber
If you‘ve tried all the troubleshooting steps but your shower still won‘t turn on, it‘s time to call a professional plumber.
A licensed plumber has the expertise to fully diagnose tricky shower problems inside your home‘s walls and behind tiles. They also have the right tools to access and repair shower components in hard-to-reach places.
Plumbers can properly replace shower valves in the wall, address issues like pipe leaks, or reroute plumbing if needed. They can also get specialty shower parts that aren‘t available at home stores.
In most cases, a plumber can get your shower running again quickly and safely. So when in doubt, call the pros to get your shower fixed and avoid frustration!
Get Your Shower Working Again!
Dealing with a shower that won‘t start up is such a headache! But in most cases, the fix is fairly straightforward – whether it‘s replacing a simple cartridge yourself or calling a plumber for repairs.
With this comprehensive troubleshooting guide, you now have all the key information needed to get your shower working again and keep it running smoothly.
Take the time to properly diagnose the issue. Don‘t give up if water doesn‘t come out at first. With targeted troubleshooting, you can enjoy great water pressure from a fully functioning shower valve very soon!