Finding water around your water heater is unsettling. You don’t know yet if it means a small part swap or a flooded utility room, and the tank isn’t telling you.
Here’s the short answer: most water heaters leak for one of six reasons. Internal tank corrosion, sediment buildup, excess pressure, a discharging temperature and pressure (T&P) relief valve, a worn drain valve, or loose fittings at the top of the tank. Internal corrosion is the most common cause we find, and it almost always shows up as a leak from the bottom.
We’re Abend Services, a family-run Maryland plumbing and HVAC company that’s been working on water heaters since 1952, and the location of the leak tells us most of the story before we even open our toolbag. If water is actively pooling right now, turn off the cold-water supply to the tank, shut off the power or gas, and call a licensed plumber in Severna Park or anywhere else in Anne Arundel County. A pro can usually tell you within minutes whether you’re looking at a quick fix or a failing tank.
If the leak is slow, you have time to read this first. By the end, you’ll know what’s likely wrong, what’s repairable, and the one type of leak that’s actually a safety warning in disguise.
Before we get into causes, use this quick sort. We call it the Abend Leak Triage, and it’s the same first check our techs run on every call: top, bottom, or valve.
| Where the water is | Most likely cause | Repair or replace? | How urgent? |
| Top of the tank | Loose cold-water inlet, hot-water outlet, or T&P fitting | Usually repairable | Schedule soon, check it daily |
| Bottom of the tank, steady leak | Internal corrosion, the tank itself has failed | Replacement | Urgent, this won’t improve |
| T&P discharge pipe | Pressure or temperature above safe limits | Needs diagnosis, not just a new valve | Urgent, it’s a safety signal |
| Drain valve near the floor | Worn or loose drain valve | Repairable | Urgent if water is flowing freely |
| Puddle with no visible source | Condensation or a slow hidden leak | Needs inspection | Soon, before it spreads |
Now let’s look at why each of these happens, starting with the one that ends the most tanks.
About 97% of U.S. water heaters are traditional storage-tank models, according to the U.S. Department of Energy. Inside that steel tank is a thin glass lining and a sacrificial anode rod. The rod’s whole job is to attract corrosive elements so the steel doesn’t have to.
Once the anode rod is more than 75% depleted, it should be replaced. When it’s gone and nobody swaps it, corrosion starts eating the tank itself. That’s why a lack of routine maintenance is behind so many of the corrosion leaks we find.
Here’s the hard part to hear: a leak from the bottom of the tank means the metal has already broken down. At that point the structure has failed, and it’s a replacement conversation, not a repair.
If your water heater pops or rumbles, that’s water boiling underneath a layer of sediment. Sediment slows heat transfer, makes the unit work harder, and over time can stress the tank enough to cause a leak.
This one matters more in some parts of our county than others. More on that in a minute.
Water expands as it heats. Water at 145°F takes up more space than water at 125°F, and that extra volume raises pressure inside a closed tank. The usual pressure culprits are elevated water temperature settings, excessive supply pressure, or a failed thermal expansion tank or relief valve.
Water dripping from the T&P discharge pipe often gets reported to us as a leak. It’s actually the safety system doing its job. Residential T&P valves are built to open at 150 psi or 210°F under ASME, ANSI, and CSA standards, releasing pressure that has nowhere else to go.
Gavin Urban of WireNut has warned that a tank with no way to release that built-up pressure can eventually rupture, and in extreme cases burst. So a discharging valve is good news and bad news at once. The safety device works, but something is pushing your system past its limits, and that underlying cause needs a professional diagnosis. Never cap or plug a T&P valve.
The drain valve sits near the floor, and when it wears out, water can flow freely from the tank. It’s one of the first things our techs check because it’s a common and fixable failure point.
Leaks from the top usually trace back to the cold-water inlet, the hot-water outlet, or the T&P valve connection. These are generally the best leaks to have, because they’re often repairable without replacing the system.
Not sure which bucket your leak falls into? Abend Services answers the phone 24/7 across Annapolis, Arnold, Crofton, Glen Burnie, and the rest of Anne Arundel County. Describe what you see and we’ll tell you honestly whether it can wait until morning.
This is the part most water heater articles skip, because most aren’t written for this county.
Anne Arundel County draws its water from deep Coastal Plain aquifers, including the Patapsco, Patuxent, and Aquia, through 12 treatment facilities producing roughly 12.6 billion gallons a year. Annapolis runs its own separate system. County water quality data shows most of that groundwater is comparatively soft, below 100 mg/L hardness.
But there are two big exceptions:
In other words, your corrosion and sediment risk partly depends on which water source feeds your home. Add Maryland’s cold winters, which bring bigger temperature swings and extra thermal expansion strain, and older homes near the Chesapeake Bay watershed have a few more reasons to keep an eye on the tank.
The age of your tank predicts a lot. The Insurance Institute for Business & Home Safety (IBHS) found that the average failed water heater is 10.7 years old, and by age 12, nearly 3 in 4 have failed. The same research shows 69% of all water heater failures come down to a slow leak or a sudden burst, making water heaters one of the top five sources of residential water damage.
The stakes aren’t small. A residential tank holds 20 to 80 gallons, and IBHS data puts the average water heater failure claim at $4,444, with a leaking or burst unit typically adding over $3,000 in property damage beyond the unit itself.
“A relatively small amount of water can do a lot of damage.”
Daniel Fielding, quoted in PHCPPros on water heater shutoff valves
The practical takeaway: if your tank is past year 10, treat any leak as a sign to start the replacement conversation, even if a repair buys you some time.
Usually only partly, and the details matter. Standard homeowners insurance typically covers sudden water damage caused by a water heater, but not the repair or replacement of the unit itself. Damage from age and gradual deterioration is typically excluded as normal wear and tear, because insurers expect homeowners to maintain their appliances.
That second point is the one that catches people. A slow leak you noticed and ignored can undermine your claim. Acting early protects your floors and your coverage at the same time.
The broader numbers explain why insurers care. A 2025 Insurance Information Institute report based on 2023 data found water damage and freezing accounted for 22.6% of all home insurance claims, second only to wind and hail. From 2018 to 2022, the average payout for those claims was $13,954, and roughly 1 in 60 insured homes file one each year. Remediation experts note that removing just one inch of water from a single floor of a small home can cost several thousand dollars.
For specifics on your own policy, your insurance agent is the right call. For stopping the leak, that’s us.
Yes. In Anne Arundel County and most Maryland jurisdictions, a plumbing permit is required to replace a water heater, even in a like-for-like swap. In Maryland, a licensed master plumber or plumbing contractor must obtain the permit before work begins, and residential tank replacements require inspection before use.
That inspection verifies venting, pressure relief valve placement, and gas connections. Skipping it can create safety hazards and complicate a future home sale. A licensed pro handles all of this as part of the job, which is one more reason a leaking tank isn’t the place to cut corners.
It comes down to two things: where the leak is and how old the tank is. Top fittings, drain valves, and pressure issues on a younger tank usually point to repair. A bottom leak, or almost any leak on a tank past year 10, points to replacement, and the IBHS failure data above backs that up.
There’s also a regulatory clock worth knowing about. The Department of Energy’s water heater efficiency rule took effect July 5, 2024, with compliance required on and after May 6, 2029. Electric storage units over 35 gallons will require heat pump technology, and DOE projects over 50% of new electric storage water heaters will use it, up from about 3% today. Then-Energy Secretary Jennifer Granholm said at the time that outdated efficiency standards had been driving up utility bills for years. One clarification, since older articles get this wrong: the separate rule for gas tankless units was withdrawn in May 2025, so these 2029 changes apply to storage water heaters.
Whether to replace before 2029 depends on your home, your fuel type, and your tank’s condition, so it’s worth a conversation rather than a guess. If your unit is past year 10 and leaking from the bottom, it usually makes more sense to compare water heater replacement and installation options than to keep patching a tank that the data says is near the end.
And on cost: pricing depends on your unit, fuel type, venting, and home setup, so we’d rather give you a real quote than a number that turns out wrong. Call Abend Services and we’ll put an honest figure on it.
A leaking water heater rarely fixes itself, but caught early, it’s often a manageable repair instead of a flooded room and an insurance claim. Shut off the water, note where the leak is coming from, and let a licensed plumber confirm what the tank is telling you.
We’ve been doing exactly that for Maryland families since Carl and Catherine Abend founded the company in 1952, and we’ve been woman-owned under Katie Abend since 2014. Our team offers 24/7 emergency service across Annapolis, Arnold, Brooklyn Park, Crofton, Glen Burnie, Millersville, Odenton, Parole, Pasadena, and Severna Park. If your water heater is leaking, dripping, or just making noises you don’t trust, call Abend Services and we’ll take it from there.
It depends on the source. Water flowing from the bottom of the tank or gushing from the drain valve should be treated as urgent, and a discharging T&P valve is a safety signal that needs same-day attention. A slow drip from a top fitting can usually wait for a scheduled visit. When you’re not sure, shut off the water supply to the unit and call. That step alone limits most damage.
It’s rare, and the T&P relief valve exists specifically to prevent it by opening at 150 psi or 210°F. Water coming from that valve means the safety device is working. The real concern is the underlying pressure or temperature problem causing it to open, which a licensed plumber should diagnose promptly.
We can’t responsibly answer that without seeing the unit, because it depends on where the leak is and how fast it’s growing. The safest move is to shut off the supply and have it assessed before continuing to use it.
Honestly, there’s no reliable universal answer, and anyone who gives you one is guessing. A loose fitting might drip unchanged for weeks, while a corrosion leak only gets worse. What the data does show is that nearly 3 in 4 water heaters have failed by age 12, so an older leaking tank is living on borrowed time. An inspection is the only way to know what yours will do.
It’s either condensation or a slow hidden leak, and they look identical at first. Dry the area, lay down paper towels, and check back in a few hours. If the water returns, have the unit inspected before assuming it’s harmless.
All Service Areas
