Hot water tank issue (rust or other buildup?)

Question

I recently noticed the water coming out of my hot water has taken on an orange/dirty colour so decided to do some maintenance on the hot water tank. Below is what I’ve tried so far over the span of 2 weeks, the water has kept the same discolouration - some improvement but not clear like when I compare to water out of my cold water tap. It’s certainly not as bad as when is started but still there. I’m at a loss as to what to try next, do I have any other options or is next step to replace the tank?? Thanks!

1. I flushed the tank two weekends in a row now trying to get the water coming out to be as clear as possible. Tank continues to have small particulate flowing out when I flush but nothing I would consider excessive (probably rust as it was attracted to a magnet when I ran one through the water)

2. I replaced the anode with a new one, the previous anode was completely gone to the core (probably never replaced before). Water tank is 7 years old and I live in a very hard water area + have a water softener. I’m suspecting the tank has probably started rusting inside but not sure how bad.

3. There are no leaks or dripping water around the tank that I can tell.

4. As a last ditch effort I bought an endoscopic camera to see what’s going on in the tank itself. Below are the best pictures I could produce given the conditions (fed through the hot water inlet when tank was empty)

first 2 pictures are where tank walls meets bottom - you can see sediment that looks like small rust particles, second picture is of the wall, there’s lots of buildup like this at the top of the tank? Is this rust or something else and is this what’s causing my water discolouration? Anything to be done?

Answer 1

That's as good an excuse as any for buying an endoscope. I've wanted one for a while.

You did not say if you have hard or soft water. That matters.

I think your tank is too far gone. Tanks that do not get anode rod replacements are typically good for 8-15 years depending on usage. Tanks that do can go from 15-25 years that has been my experience. Your tank has been missing an anode rod for a long time now.

If you have hard water you should be periodically draining sediments. If you have very hard water you should replace the dip tube with a curved dip tube. This allows the tank to be drained then all of the sediments to be expelled. If you don't do this then they build up on the bottom and cause the bottom of the tank to overheat which damages the glass and causes the tank to start rusting.

The tank is steel with vitreous glass bonded to the inside. The glass does not perfectly cover all the steel in the tank which is why there's an anode rod.

If you have copper pipe there should be dielectric fittings used.

The hotter the temp you keep the water heater the faster it will corrode.

Answer 2

If you have copper pipes I'd replace the tank. Rust will cause pin hole leaks to develop in copper pipes.

I have a 25 year old tank, never replaced the anode, I flushed it probably 10 years ago and water was orange. I don't notice my hot water being dirty though even though I am sure the tank is rusty though I don't drink the hot water. Typically the hot water is drawn from the top of the tank so if the water is still rust should settle. Are you typically drawing hot water until it is cold? Where is your hot water output - is it at the top of the tank?

The one time I had a problem like you describe is where one of the elements went and it was putting out the rusty color but in that case I think the water wasn't reaching temperature either. That was in an electric hot water tank where the element died when it was turned on while exposed to air.

Answer 3

You have really worked hard at this! While you have the endoscope, try to get a look inside where each of the pipes screw on. If you can see a pattern of cracks in the glass (assuming a glass-lined tank) then you know that the connections were over tightened, and the tank's life is coming to an end.

Answer 4

What a water softener does is replace the calcium and iron and other minerals in the water with sodium. The good part from a tank perspective is that calcium build up inside the tank is not removable once it bonds to the tank (unless you fill the tank with acid or some such) So putting the hot water heater behind the water softener is the correct thing to do. The BAD part is that sodium is MORE corrosive than calcium.

In an area with very corrosive water you should be looking at replacing the anode rod (or at least checking it) every 2 years. THE ANODE ROD ALWAYS IS ATTACKED FIRST by corrosion. So as long as it exists you are fine.

Anode rods are constructed with a steel core covered with aluminum or some other alloy. Because there is a continuous current flowing through them they are attacked from the top down - that is the material is consumed at the top (because it has the least amount of electrical resistance to the tank) and then disintegrates all the way down to the end of the rod. Once the anode is used up all that's left is a thin steel rod hanging down which then usually breaks off and falls into the tank. Unfortunately because of the way the rods are consumed sometimes the unused anode material will break off the rod and fall into the tank also.

Your tank SHOULD be dated. Look at the sticker. What is the incept date? Tanks - with maintenance - can last a VERY long time. We bought a house 2 years ago with a tank in it that was manufactured in 1994 and is still going strong. Soft clear water, low temps, and maintenance can greatly extend tank life. Hot sodium water and ignoring maintenance - bye bye tank.

WHY is the water hard? What mineral is in it? If it is hard due to iron in it then it's quite possible the iron you are seeing in the water has nothing to do with the tank at all. Maybe the water softener is not working well. You SHOULD have a tap BEFORE the water softener draw off a 5 gallon bucket of water from it and look at it.

My recommendation is this - change the anode rod. Create a paper rod inspection schedule and put it on the tank. Install a water leak sensor below the tank and hook it to your home automation system and forget about the tank. Iron is a needed mineral and your wife is probably taking iron tablets with her vitamins so she can quit wasting money on the pills. In fact it is far far healthier for you to make use of the upstream tap and keep a jug of water in the refrigerator that is drawn off the tap BEFORE it goes into the water softener. Calcium is another important body mineral and you probably have a free supply of it in your water so quit worrying about it.