When the hot water turns “meh” overnight
You know that moment when you’re washing dishes and the water never really gets hot, or the shower goes lukewarm halfway through? In San Antonio, TX, that can feel extra annoying because we lean on our water heaters year-round and hard water can be tough on them.
If you have an electric water heater, one of the most common culprits is a burned-out heating element (the metal part inside the tank that heats the water, kind of like an oversized electric stove coil). The good news: you can test an element with basic tools and a little caution, and you’ll know whether you’re chasing the right problem before you buy parts.
What a water heater element is and why it matters
Most electric water heaters have two heating elements: an upper element that heats the top of the tank first, and a lower element that does the heavy lifting to keep a full tank hot. Each element is controlled by a thermostat (a temperature switch that tells the element when to turn on and off).
When an element fails, your symptoms can vary. A lower element failing often looks like “some hot water, then it runs out fast.” An upper element failing can leave you with barely warm water at all, because the tank never heats properly from the top down. Testing helps you confirm whether you’re dealing with a dead element, a thermostat issue, wiring trouble, or even a tank problem.
The usual reasons homeowners end up with cold water or short hot showers
In real homes, it’s rarely “just one thing.” Here are the most common ways an element ends up looking guilty:
A burned-out element is the classic one. Over time, the element can overheat and fail electrically, so it no longer heats even though the heater has power.
Mineral scale is the sneaky one. Hard water leaves calcium and magnesium behind as it heats, and that buildup can insulate the element like a crusty blanket. In the SAWS service area, typical water hardness ranges around 15 to 20 grains per gallon, which is firmly in “very hard” territory and can contribute to scale. That’s straight from SAWS water quality FAQs.
Loose wiring or a tripped reset can also mimic a bad element. A heater can have power at the breaker but still not deliver heat if a connection is cooked, a wire is loose, or the high-limit safety reset has tripped.
A simple checklist to test your element safely
Before you touch anything, safety comes first. Electric water heaters can seriously hurt you if you test them “live.” Here’s the clean, homeowner-friendly way to do it:
- Turn off the breaker for the water heater (not just the wall switch, if you even have one).
- Confirm power is off with a non-contact voltage tester, then double-check with a multimeter at the heater terminals.
- Remove the access panel(s) and peel back insulation carefully so you can see the thermostat and element terminals.
- Press the red reset button on the upper thermostat once (if it clicks, that’s useful information).
- Set your multimeter to ohms (resistance) and touch one probe to each element screw terminal.
- Check for a “short to ground” by touching one probe to an element terminal and the other to the metal tank.
- Compare the upper and lower readings; one bad element often stands out.
That’s the whole test in plain language. The details matter, so let’s make the results make sense.
Reading the results without overthinking it
Your multimeter “ohms” reading is basically telling you whether electricity can flow through the element properly.
A healthy element usually shows a steady resistance number instead of jumping around. If your meter reads OL, infinity, or never settles, the element is likely “open” (burned out internally). If it reads extremely low (close to zero), it may be shorted.
The ground test is just as important. If you get any reading when one probe is on an element screw and the other is on the tank metal, that suggests the element is leaking electricity to ground. That’s a hard stop, because it can trip breakers and create a safety hazard.
One more tip: don’t assume “bad element” just because hot water feels weak at the sink. A lot of homes have low-flow aerators or faucets that limit output to save water. EPA notes that WaterSense-labeled bathroom faucets and accessories use a maximum of 1.5 gallons per minute and can reduce flow compared to older setups, which can change how “strong” hot water feels at the tap even when heating is fine. That’s explained on EPA WaterSense bathroom faucets.
If the element fails the test, what to do next and what not to do
If your test points to a failed element, replacing it is often straightforward, but there are a few traps that create bigger problems.
First, match the replacement element to your heater’s voltage and wattage (usually stamped on the element flange or shown on the water heater data label). Don’t “upgrade” wattage thinking it will heat faster. That can overload wiring or shorten the heater’s life.
Second, don’t reuse a flattened or brittle gasket. A tiny leak at the element can drip into the access area and cause corrosion or shorts.
Third, be gentle with older plumbing connections. If you shut off water to drain the tank and your shutoff valve is old, forcing it can snap the stem or start a slow leak. Also, if you open the T&P valve (temperature and pressure relief valve) to help draining, don’t crank on it aggressively. If it won’t reseat after, you’ll need it replaced.
And one important “don’t”: don’t buy random parts of unknown quality for anything that touches your drinking water. Look for parts that meet potable-water safety expectations, such as components evaluated to NSF/ANSI 61 (a standard for materials that contact drinking water). NSF explains what this standard covers on its page for NSF/ANSI 61 drinking water system components.
How to confirm the fix is solid over the next few days
A water heater can look “fine” the first hour and then show you the truth later, especially if there’s a tiny seep or a wiring issue.
After replacing an element or tightening anything inside the access panels, fill the tank completely before restoring power. Running an electric element dry can burn it out fast.
Once the tank is full and you turn the breaker back on, give it time to recover temperature. Then check for a steady supply of hot water through normal use. Over the next couple of days, open the access panels once more and look for any dampness, mineral streaks, or darkened wiring insulation. A flashlight and a dry paper towel are your best friends here.
Also listen. A bit of soft “hiss” while heating is normal. Loud popping or crackling can be a sign of scale buildup on the element or sediment in the bottom of the tank.
When calling PlumbSmart is the cheaper option
If your meter test clearly shows a bad element, a confident DIYer can replace it. But if your readings are confusing, the breaker won’t stay on, or you see heat damage on wiring, it’s smart to stop and bring in a pro.
You’ll also save money by calling sooner if the tank is older, heavily scaled, or leaking. In San Antonio, TX, hard water can accelerate wear, and sometimes the “element problem” is really a tank that’s struggling with sediment and corrosion.
PlumbSmart can help whether you need a targeted fix or a bigger plan:
- If you want a diagnosis and repair without guesswork, start with water heater repair.
- If you’re trying to prevent repeat failures, routine flushing and checks through water heater maintenance can extend the life of the heater.
- If scale keeps chewing through fixtures and equipment, a water softener installation can make a noticeable difference across the whole house.
The goal isn’t to upsell you into something you don’t need. It’s to keep a small repair from turning into a flooded garage or a full replacement you didn’t plan for.
The three smartest moves before you buy parts
If you take nothing else from this, do these three things and you’ll avoid most homeowner mistakes.
Make it safe first: shut off the breaker and confirm the power is truly off before you touch any terminals.
Test instead of guessing: check resistance across the element terminals and check for a short to ground, so you know whether the element is actually the problem.
Plan for your water conditions: in very hard-water areas, element failure and scale can go hand-in-hand, so think beyond “swap the part” and consider maintenance and buildup control.
If your results point to a failed element, you’re already ahead of the game because you’re making decisions based on evidence, not frustration.
