The little “popcorn” sounds that turn into cold showers
If your water heater has started making crackling or rumbling noises, or your hot water doesn’t last like it used to, it’s usually not “just getting old.” It’s often sediment (tiny mineral bits) piling up in the bottom of the tank. In San Antonio, TX, hard water can make that buildup happen faster than many homeowners expect. Draining and flushing your tank is one of the simplest ways to keep hot water steady, help the heater run more efficiently, and catch small problems before they turn into a leak.
This is a homeowner-friendly job, but it’s also one that gets messy fast if you skip the safety steps. The good news: if you take it slow, it’s very doable.
What draining a water heater actually does
“Draining” a water heater usually means removing water from the tank through the drain valve near the bottom. When you do it correctly, you’re also flushing out sediment. That sediment is mostly mineral scale, which is hardened calcium and magnesium that drop out of the water as it’s heated.
Here’s why that matters beyond comfort: sediment creates an insulating layer between the burner or heating element and the water. Your heater has to work harder to heat the same amount of water. Over time, that can shorten the life of parts inside the tank, and it can even reduce your hot water capacity because the bottom of the tank is basically filled with “rocky soup” instead of usable hot water.
Draining also gives you a chance to notice early warning signs, like rusty water, a weeping relief valve, or a drain valve that’s starting to seep.
Why homeowners get stuck halfway through
Most water heater draining problems come from a few predictable missteps. One is trying to drain before letting the water cool down. Hot water can cause serious burns, and it can soften cheap hoses so they kink or burst.
Another common issue is forgetting that a tank needs air to drain smoothly. If you don’t open a hot water faucet somewhere in the home, the tank can “glug” and drain painfully slow because it’s fighting vacuum pressure.
The most expensive mistake is turning power back on too early. An electric water heater element (the metal heating part inside the tank) can burn out quickly if it heats while the tank is empty or only partly full. Gas units have their own risk: relighting incorrectly or letting the burner run without proper water flow.
Finally, some drain valves are honestly just flimsy. Sediment can clog them like sand in a straw, and you’ll get a trickle instead of a drain.
A simple, safe draining checklist you can follow
Use this step-by-step approach to drain and flush a typical tank water heater:
- Turn the heater off: set gas to “pilot” or “off,” or switch off the breaker for electric units
- Let the water cool for a few hours if possible (warm is safer than hot)
- Shut off the cold water supply valve feeding the heater
- Open a hot water faucet in the house to relieve pressure and let air into the tank
- Attach a hose to the drain valve and run it to a safe drain point (floor drain, tub, or outside)
- Open the drain valve slowly and let the tank empty
- If you’re flushing sediment, briefly open the cold supply valve in short bursts to stir up debris and push it out
- Close the drain valve, remove the hose, and open the cold supply fully to refill
- Keep a hot faucet open until air stops sputtering and you get a steady stream
- Only restore power or relight the burner after the tank is completely full
Flow, pressure, and the “weak hot water” myth
A lot of homeowners describe the problem as “my hot water pressure is low.” Most of the time, your water pressure is fine. What you’re noticing is reduced flow (how much water comes out per minute), often measured in gallons per minute (GPM). Flow can drop when faucet aerators clog with mineral grit, when shutoff valves are partially blocked, or when sediment buildup affects how the heater keeps up with demand.
If you want a reality check on flow at the sink, it helps to know what “normal” even is. WaterSense-labeled bathroom faucets are designed to use no more than 1.5 GPM, which is one reason they save water without feeling unusable. That baseline can help you tell the difference between “efficient” and “something’s wrong.” (EPA WaterSense bathroom faucet guidance)
Now the local factor: San Antonio, TX water hardness is driven by naturally occurring calcium and magnesium. Those minerals can leave scale behind as water moves through soil and rock, and that scale can settle and harden inside a water heater. SAWS describes hardness as the concentration of calcium and magnesium, typically expressed as calcium carbonate, and notes it’s naturally occurring in local aquifer water. (SAWS water quality FAQ on hardness) That’s why routine flushing matters here, even if your heater seems “fine.”
What to do if draining uncovers a bigger issue
Sometimes draining a heater doesn’t go smoothly, and that’s not always your fault. Here’s what to watch for, and what not to do.
If the drain valve won’t open, don’t force it with a wrench until it snaps. A broken drain valve can turn into an uncontrolled leak fast. If it opens but nothing comes out, sediment may be blocking the valve opening. You can try closing the valve, opening the cold supply for a few seconds, then reopening the drain to see if it clears. Keep the hose secured and the drain route clear, because a clog can suddenly release.
If water leaks from the valve stem or around the hose connection, stop and reassess. Tightening gently can help, but overtightening can crack plastic valve parts.
If you notice a sewer smell while draining into a floor drain, that can point to a dry trap (the U-shaped pipe that holds water to block sewer gas). Running a little water down the drain afterward usually fixes that, but persistent smells can mean a venting or drain problem that deserves professional attention.
If you hear banging after refilling, that may be water hammer, which is a pressure shockwave that happens when water stops suddenly in pipes. Don’t ignore it. It can damage valves and supply lines over time.
Also, avoid using random garden hoses or sketchy adapters that aren’t meant for drinking water systems. If you’re connecting anything that contacts your home’s water, look for products rated for potable water. Standards like NSF/ANSI 61 exist to set minimum health-effects requirements for materials that contact drinking water, which is exactly what you want for fittings, valves, and components tied into the system. (NSF overview of NSF/ANSI 61)
How to confirm everything is back to normal
Once you’ve refilled the tank, the goal is to be boring. No drips, no sputtering, no strange noises, no temperature surprises.
Start by checking the area around the water heater base and the drain valve. Dry everything with a towel so you can spot fresh moisture. Then look at the temperature and pressure relief valve (often called the T&P valve, a safety valve that releases water if pressure or temperature gets too high). You’re not pulling the lever here, just checking that it’s not actively dripping.
Next, run hot water at a nearby faucet until the air clears and the stream is steady. That sputtering is normal at first because air pockets are leaving the lines. If it keeps spitting for several minutes, the tank may still be filling or a valve may be partly closed.
For electric heaters, do not flip the breaker on until you are confident the tank is full. A quick test is opening a hot faucet and confirming a strong, steady flow. For gas, follow the relight instructions on the heater’s label exactly.
Over the next day or two, do a quick cabinet and floor check. Slow leaks love to show up after things cool down and contracts slightly.
When calling PlumbSmart is the cheaper option
If your drain valve won’t open, sediment won’t flush, or the tank shows any signs of leaking, this is the moment to stop “powering through.” Water heaters fail in a hurry once the wrong part gives out, and water damage is rarely a small bill.
A pro can flush the tank more effectively, replace problem valves, and spot warning signs you might miss, like venting issues on a gas unit or a failing expansion tank (a small tank that absorbs pressure changes in closed plumbing systems).
If you’d rather have it handled safely and cleanly, PlumbSmart can help with routine water heater maintenance and troubleshoot problems before they turn into a no-hot-water weekend. If draining uncovered a leak or your unit won’t heat properly afterward, schedule a water heater repair so you’re not guessing. And if hard water buildup keeps coming back year after year, a whole-home solution like water softener installation can reduce scale that chews up heaters, faucets, and valves.
Wrap-up: the three moves that make this go smoothly
Draining a water heater is one of those home tasks that feels optional until it suddenly isn’t. Keep it simple and you’ll get the benefits without the mess.
First, prioritize safety: shut off power or gas, and let the water cool. Second, flush with purpose: drain fully and rinse out sediment until it runs clear. Third, plan for your water conditions: if mineral buildup is common where you live, make this a regular habit so your heater stays quiet, efficient, and reliable.
