Water heater going hot and cold with weird refill noises
Old water heaters can experience erratic temperature swings, long periods of running cold after heavy use, and strange refilling cycles. These sudden failures leave you without reliable hot water and make standard maintenance risky due to severe internal calcification, forcing homeowners to question whether to repair or replace the failing unit.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1replacing the entire water heater unit
- 2trying to DIY repairs on gas components
- 3replacing failing parts like gas valves or thermostats
- 4Contacting the previous owner to ask about the maintenance history and checking the condition of the drain valve.
- 5Cutting and coupling the PEX pipe back together
- 6Unscrewing the hot dielectric nipple
- 7Leaving the anode rod unserviced
- 8using emergency savings funds
- 9Switching to an electric anode rod
- 10Inspecting the anode rod yearly if using a water softener
- 11Putting a Tupperware container under the leak
- 12Running a dehumidifier in the basement
- 13Calling a plumber for an inspection
- 14Budgeting for an early replacement
- 15Leaving the water heater unflushed to avoid potential damage
- 16Considering a single repair option instead of replacement if the unit is not leaking.
- 17Trying to flush the unit and inspect connections to figure out if an anode rod was installed incorrectly.
- 18leaving the water heater alone and letting it run until it fails
- 19saving money for a future replacement
- 20replacing only the anode rod while skipping the flush
- 21setting up protection near a sump pit in case of leaks
- 22Hiring a plumber to replace the unit
- 23Buying a shorter model to fit spatial constraints
- 24Replacing the rusted gas shutoff valve
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“My electric water heater leaks above the upper thermostat/electrical compartment, but only when the cold water supply valve turn on..”source ↗
“Awesome, RIP to the $800 I was saving toward a new graphics card. My water heater saw my bank account and said, "That's mine now."”source ↗
“I've shut off our water heater, and I have a plumber coming out tomorrow morning to replace our current 40gallon heater with a shorter 40 gallon.”source ↗
“we don't have much space to drill a hole higher in the chimney to reroute the current exhaust.”source ↗
“I'm admittedly out of my depth with a lot of this stuff”source ↗
“Installed a new water heater 3 years ago. It came with an aluminum rod. This is what was left of the rod when I removed it.”source ↗
“Noticed this small amount of water coming from the bottom of the water heater.”source ↗
“Would you let it ride or try to flush and replace rod?”source ↗
“I’m unsure of what, if any, maintenance was done by previous owners over the years, but a plumber that came out for a different issue looked at the hot water tank and strongly advices against flushing it or doing any other main tender due to its age and calcification.”source ↗
“Is that sound advice? He was very pushy about advising I replace it now due to its age, so makes me question his advice on maintenance.”source ↗
“I’m a new homeowner and started getting black specs in my hot water. I’m flushing the tank and finding black specs in here. Maybe it’s the anode rod, maybe not.”source ↗
“How am I supposed to service the anode rod with this sort of set up? This particular tank has the anode rod as part of the hot water supply.”source ↗
“Since its not the TandP valve, I'm gonna say the tank is done. You're sure its not a pipe up top leaking and running down?”source ↗
“My parents had a tank that was going on 12 years with zero maintenance, never flushed, anode was just a sad little wire when we finally pulled it. Dad decided to flush it and the thing started leaking within a week.”source ↗
“Just had this happen to me over the weekend. Small leak on Wednesday and I thought "eh, seems like a weekend problem" and just throw a Tupperware container under it.”source ↗
“Difficult to say for sure. Leak doesn't appear to be originating from any of the visible plumbing. Very small amount of water at the base of the tank on the other side. Sounds like the tank itself, any ideas on how urgent this is to get replaced?”source ↗
“I had a 20yr old tank that wasn’t being maintained, sprung a leak 4 years into ownership because I wasn’t aware anode rods are a thing.”source ↗
“My water heater is 2 years old and I don’t know if it’s been flushed before (probably safe to assume not because previous owners were not very good with maintenance tasks). My question is, is it risky to flush it now? Or is it new enough that it should be okay?”source ↗
“since we moved in, we’ve intermittently had an issue with the water heater not keeping water hot after hours of no hot water use, water being way too hot when it is hot, and 12+ periods of it seeming to try and refill after using a large amount of hot water.”source ↗
“Recently, the issues have become much more frequent, leaving our water cold more often than it is hot.”source ↗
“My water heater has finally failed, water doesn’t get hot only luke warm.”source ↗
“good replacements for under a grand?”source ↗
“i called three plumbers, the all said i needed to replace it.”source ↗
“It is an AO Smith 40 gallon model and where the anode rod should be on top next to the cold inlet port it looks like the installers put the pressure relief valve and drain pipe.”source ↗
“My question is am I seeing this correctly? How could a water heater be installed by a major gas company without the anode rod and if so, how badly am I in trouble?”source ↗
“It is dripping from this uncapped pipe. Any ideas what this is? I can't disprove that the tank is leaking, but i got this pipe dripping on video.”source ↗
“My confusion is that the female is tied into the pex so when I start twisting that off, it will move the pipe with it. No?”source ↗
Where this came up
People with this problem also raised
- 3Why is there water on the floor around my new water heater?
- 6Why does a new water heater require so many infrastructure upgrades?
- 2How to deal with failing and rusted galvanized pipes
- 2Why is my tap water suddenly rusty and full of sediment?
- 2Where to cut a cramped water heater cold line?
- 3Why do older houses have no outlets?