Quick Answer:
If your newly remodeled shower now takes much longer to get hot, the most likely causes are a mis-set or mis-installed valve cartridge, added flow restrictors, or a rerouted hot supply with a kink or long dead leg. Start by comparing how long hot water takes at other fixtures, then check the valve cartridge orientation and anti-scald setting and inspect any newly installed flexible lines or restrictors.
Why This Happens
Remodels often change the parts the water passes through. New mixing valves, cartridges, diverters or showerheads can add small delays before hot water reaches the shower head. A longer or rerouted hot pipe increases the travel distance. If flexible supply lines were used, they can be kinked or pinched in the wall during installation. Finally, flow restrictors and some thermostatic anti-scald settings deliberately slow or limit hot flow.
If only the remodeled bathroom shows a delay, compare it to the rest of the house — **Delay only in one bathroom** could point to valve or routing issues rather than the water heater. If the house was recently winterized or returned to service, also check common restart causes like trapped air or isolated valves—see **Hot water delay after winterization** for those checks.
Step-by-Step What to Do
1. Measure and compare
- Run the shower and time how long until the water is hot. Note steady-state temperature and whether it slowly rises.
- Test a hot faucet at the sink and a fixture on the same floor. If they warm quickly, the problem is local to the shower.
2. Verify cartridge orientation and anti-scald setting
- Turn off the water supply to the shower (isolation or main) and remove the handle and trim to access the valve cartridge.
- Check that the cartridge is seated and oriented per the valve manufacturer’s markings: a reversed cartridge can route cold/ hot incorrectly or reduce flow.
- Locate the anti-scald or maximum temperature stop and confirm it isn’t set too low. Many thermostatic or pressure-balancing valves have an adjustable limiter that can make the shower slow to reach desired warmth.
3. Check connections and routing
- Inspect flexible supply lines and behind-trim piping for kinks or sharp bends created during the remodel.
- If the remodel rerouted hot piping, identify long runs or extra loops; longer distance means longer wait time for hot water.
- Ensure hot and cold inlet lines are connected to the correct valve ports. A swapped connection can produce sluggish warm-up or improper mixing.
4. Look for added restrictors or flow controls
- Remove the showerhead and check for a flow restrictor screen. Temporarily test without it to see if water heats faster (keep this brief to save water).
- Some new trim kits include built-in restrictors or thermostatic cartridges that limit flow. Confirm whether any new parts were included and test with them removed if possible.
5. Test the valve and diverter
- Operate the valve through the full range. If the handle feels stiff or doesn’t reach full hot position, the limiter may be catching.
- If you have a tub/shower diverter, check it for partial blockage or misalignment that could restrict hot flow to the shower head.
6. Check the water heater and house supply
- Confirm other fixtures show normal hot response. If the entire house is slow, investigate the water heater (settings, recent maintenance, or recovery issues).
- Make small tests: open a nearby hot faucet while timing the shower. This can help determine whether the delay is travel time or valve restriction.
What Not to Do
- Don’t assume remodel delays are normal—new valves can be mis-set or installed incorrectly.
- Don’t permanently disable or remove anti-scald devices to force hotter water; these protect against scalding.
- Don’t tear open finished walls without locating and labeling piping first; cutting drywall can create bigger problems.
- If you can’t access the valve or are unsure how to re-seat a cartridge, a plumber is appropriate rather than risking damage or leaks.
When to Call a Professional
- If you cannot access the valve cartridge or piping through an access panel.
- If the cartridge appears damaged, seized, or you find cross-connected inlets that you cannot safely fix.
- If there are signs of leaks, wet framing, or insulation that was disturbed during the remodel.
- If the water heater or whole-house hot supply appears to be the root cause and you’re unsure how to proceed.
Safety Notes
- Always shut off the water supply before removing valve cartridges or trim. Open a nearby faucet to relieve pressure.
- Be cautious of scalding water when testing. Set a moderate temp and increase slowly while checking results.
- Avoid electrical work while wet. If you need to remove panels that expose wiring, stop and call a pro.
Common Homeowner Questions
- Q: Why did this start right after the remodel?
A: New parts or changed pipe routing during the remodel are the most common causes—valves, cartridges, restrictors or kinks. - Q: Can I fix cartridge orientation myself?
A: Yes, if you have a clear access panel and basic tools; follow manufacturer notes and shut off the water first. Stop and call a plumber if it’s unclear. - Q: Will a longer pipe always mean a big delay?
A: Longer runs add travel time, but most delays are small. Large delays usually come from a restriction, mis-set limiter, or a blockage rather than just length.
For more related articles, see the Shower Takes Too Long to Heat Up hub.