Written by Mike Carter, Licensed Master Plumber (TN License #M-4821), FiveStar Plumbing Reviewed for accuracy by the FiveStar Plumbing technical team Published: March 3, 2023 | Last updated: July 2, 2026
Running out of hot water quickly is a condition where demand exceeds a water heater’s capacity or efficiency, often due to limited tank size, simultaneous usage, sediment buildup, or failing components.
Do members of your household frequently shower at the same time, or back to back? Do you find yourself getting frustrated with the lack of hot water available if you aren’t the first one to shower? Do you ever turn on the shower and stand there in the freezing cold, waiting for it to warm up, just to realize there’s no more hot water? If you answered yes to any of these questions, your hot water heater may not be working to the best of its ability. When your hot water heater is working properly, it should hold enough water for everyone in your household and get warm relatively quickly after adjusting the tap.
In my years running service calls across Middle Tennessee, this is one of the most common complaints we hear — and in most cases, it comes down to one of the issues below. Just last month, our team flushed a tank in a Bellevue home that hadn’t been serviced in over six years; the homeowners were shocked at how much sediment had built up, and how much of a difference the flush made to their hot water supply.
So Why Does Your Hot Water Run Out So Quickly?
Too Much Hot Water Demand at One Time
Using hot water in multiple rooms throughout the house at once could lead to a quick depletion of hot water from the water heater. This could be caused by the laundry machine or dishwasher running at the same time you are using the shower.
You may also find yourself in the middle of a shower and the water gets spontaneously boiling hot. This is typically caused by someone in the household running cold water or flushing the toilet.
If you limit how much demand you are putting on your hot water, you may be able to avoid running out so quickly. We know that when you have a full house, this can be a difficult feat, but just making a few minor adjustments could do the trick.
The Number of People in Your Home Has Increased
Although this may seem like an obvious issue, it’s not always just the fact that your family has a few new additions. It could be the fact that the people in your household are maturing and beginning to take longer showers than they used to. This could be draining your water heater at a faster rate, and could indicate that it’s time to invest in a larger tank.
Your Dip Tube Is Broken
If you are noticing more frequent issues with your temperature controls, there could be an underlying issue with your dip tube. To find out if this is what you are experiencing, you can check for small pieces of plastic that may be lodged inside your shower head or drain strainer. If you find any plastic bits, there is a good chance your water heater’s dip tube is damaged or broken.
The dip tube’s primary function is to send cold water to the bottom of the tank to get warmed up before getting sent throughout the rest of the house. If this component becomes broken or damaged, then the cold water remains at the top of the tank and gets distributed through your home. The best way to resolve this problem would be to contact your locally trusted professional plumbing company to come out and replace the dip tube as soon as possible.
Wrong Temperature Setting on Water Heater
If your water heater is not set to an appropriate temperature setting, you could be experiencing water that is way too cold or way too hot. It is best practice to always have your water heater set between 120 and 140 degrees. If it is set lower than 120 degrees, simply turn it up to 120 or higher and see if that resolves the issue.
Note: You want to be careful not to set the water heater temperature too high, because this could result in serious burns. If you have any small children in your home, the recommended water heater setting is a comfy 125 degrees. The U.S. Department of Energy also recommends 120°F as a safe default that balances scald prevention with energy savings (energy.gov water heater guidance).
Time to Replace Your Heating Element
It is common for most typical water heaters to use two different heating elements. In most cases, there is one towards the top of the tank and another towards the bottom. The lower heating element is responsible for the majority of the water heating because water heats up through convection currents. Essentially, cold water goes to the bottom of the tank and once it’s hot it naturally begins to rise to the top. Therefore, the heating element located at the top of the tank is really only being used to maintain the water temperature. If the lower heating element stops working properly, you will notice a significant change in the amount of hot water available throughout your home.
Below are a few commonly seen causes of broken heating elements:
- An electrical short in the wiring connected to the element
- A malfunctioning thermostat
- Sediment buildup on the element, causing it to overheat
Mineralized Sediment Buildup on Your Water Heater
Over time, it’s not uncommon for sediment to begin to build up inside your water tank. If you aren’t performing annual system flushes as a part of your plumbing maintenance, this could be the reason your hot water is running out so quickly. Sediment buildup can be from sand, rust, or silt that take up space inside your water tank. This could also be affecting your heating elements, as we discussed above. If the sediment buildup is on the heating elements, the sediment would be getting hot instead of the water. Flushing out your entire water heating system is the only sure way to fix the issue entirely. Although it is possible to perform this on your own, you are much better off calling a professional plumber from FiveStar who can properly drain your water tank without the risk of a flood.
One way to avoid running into these issues is to set up annual water heater maintenance with your locally trusted plumbing company. This will help you minimize the risk of running into sediment buildup problems and also allows us to look for potential leaks or broken dip tubes. Related: see our water heater maintenance plans and water heater installation services for more on keeping your system in top shape.
Surpassing Your Gallons Per Minute (GPM) Capacity
Sometimes we find ourselves running a load of laundry and the dishwasher at the same time that another household member is in the shower. There’s a really good chance you are exhausting your water heater to its limits. It’s important to decide which hot water utilization is the most important at that time. Prioritize times for running dishes, laundry, and showers to make sure the hot water heater isn’t being overworked. Oftentimes this can simply be because the shower and the kitchen sink are both using hot water at the same time. Another example would be running the dishwasher and then heading up to take a shower — this can exhaust a tankless water heater way past its limit. One way to resolve this issue is to install more than one tankless water heater in your home, connected in parallel to allow for more capacity. There’s also the option of installing separate tankless water heaters for each appliance, such as a dishwasher or laundry machine.
Contact FiveStar Plumbing For All Your Water Heating Issues
FiveStar Plumbing has been proudly serving the Greater Nashville Area for over 40 years. Our team of experienced and qualified technicians is ready to assist you with any commercial or residential plumbing issue that may arise. Simply give us a call at (615) 382-8131 to schedule an appointment or same-day service today!
Frequently Asked Questions
Why does my hot water run out so fast?
Most often it’s because household demand — multiple showers, a running dishwasher, or laundry — exceeds what your tank or tankless unit can keep up with. Sediment buildup, a broken dip tube, or a failed heating element can also shrink your effective hot water supply even when demand hasn’t changed.
Can using multiple appliances cause hot water to run out?
Yes. Showers, dishwashers, and laundry machines all draw from the same hot water supply, so running them at once — or back to back — can drain a standard tank or exceed a tankless unit’s GPM rating.
How do I know if my water heater is too small?
If your household consistently runs out of hot water during normal daily routines (not just unusually heavy-use days), that’s a strong sign your unit’s capacity no longer matches your household’s needs — often after a move-in, a growth spurt, or a lifestyle change.
What is a dip tube and how does it affect hot water?
The dip tube channels incoming cold water to the bottom of the tank so it can heat properly before rising to be used. When it cracks or breaks, cold water mixes in near the top of the tank, so what comes out of your tap runs lukewarm or cold much sooner than expected.
What temperature should my water heater be set to?
120°F to 140°F is the standard safe range, with 120–125°F recommended if you have young children in the home, per Department of Energy guidance on scald prevention and energy efficiency.
“`html “`
