Brown hot water?

So our hot water has started coming out quite brown, according to google it apparently needs to be flushed out. This is the first i have heard of the hot water cylinder needing to be flushed out , in our other houses they were fine even after 15-20 years but we had kids at home that would empty the hot water occasionally spending too long in the shower... when they actually showered. We were also on town supply at those places so the water was clorinated, now we are on roof supplied tank water with no additives.

Is flushing the cylinder a normally needed thing on roof supplied tank water?

It's caused by bacteria and dirt getting into the system, especially after heavy rain. I think you need to watch this video and conduct a review of your whole setup.  BRANZ has a good video on how to setup a rainwater collection system.

Some interesting thoughts in there with the pickup area in the tank, and the inlet pipe. Something to think about.

In ours though the cold water coming in from the tank is fine and clear, its only the hot water that has the brown colour to it.

Had a similar problem at our bach. Problem was old galvanised pipe joiners rusting. Had to flush small quick-return cylinder then all was good.

some blame rust for brown water but you would not find many steel water heaters in NZ nor steel pipework unless it's really old. Do you have oak trees nearby as the leaves can cause brown staining? I guess the best place to start is to do a water sample test?

All the pipework i can see is plastic or copper, HW cylinder is Rheem so reasonable quality.

As mentioned we have Rimu trees overhanging the roof, so i think it is probably something connected to that but not 100% sure. Going onto tank water has been an interesting learning curve so far.

OK, Rimu leaves were used to make brown or black dyes, could have something to do with it. I think if you install a floating take off from the tank it would help, but to install it you would need to drain the tank.

Since the problem is only with the hot water, the most likely source is the hot water cylinder. It probably has a zinc anode, which is supposed to protect the other metals from attack by the water. (Rain water is dilute carbonic acid—rain dissolves atmospheric carbon dioxide as it falls.)
If that anode has been used up over the years, it may be that the steel plug it's attached to is now rusting inside the tank.
I suggest you contact Rheem for advice.

Could be Alan but it would have to be a considerable amount of steel to continually stain the water?

Rheem just said to contact a plumber to flush it out. TBH they weren't very helpful at all if you aren't a tradie. That was my first though as well but having paid enough to plumbers to come and fix stupid stuff at this place i am trying to negate as much of the spending as i can. I tried what i thought was going to be a flush on the weekend but turned out the valve that looked like it would be the exit was just the inlet bypassing the tank, bizarre as i cant imagine why you would want that.

Sigh, i guess i am spending more money on a tradesman again...

tonybaker wrote:

Could be Alan but it would have to be a considerable amount of steel to continually stain the water?

 

Possibly, but it wouldn't hurt to check out the anode anyway. 

It may also be that the OP's cold water is also a bit stained, but looks cleaner than when it's heated. I did first-year chemistry at university, but that was sixty years ago, and if I ever knew what naturally-occurring water-soluble chemicals go brown with heat I have certainly forgotten it.

mattib wrote:

Rheem just said to contact a plumber to flush it out. TBH they weren't very helpful at all if you aren't a tradie. That was my first though as well but having paid enough to plumbers to come and fix stupid stuff at this place i am trying to negate as much of the spending as i can. I tried what i thought was going to be a flush on the weekend but turned out the valve that looked like it would be the exit was just the inlet bypassing the tank, bizarre as i cant imagine why you would want that.
 

Is that actually the tempering valve? (That's the gadget where the hot feed from the top of the cylinder is mixed with a bit of cold to ensure that the resulting hot water at the taps in the house is not so hot as to scald the user. The water in the cylinder should at a high enough temperature to kill Legionnaire's bacteria (>60°), but the water at the tap should not be above about 45-50° IIRC.)

what does the inside of your jug look like? Is it brown as well or lots of scale? Try heating a saucepan of cold water on the stove and see if there is any discolouration.

Inside of the jug looks fine, previously boiled water is nice a clear. No visible scale or discolouration.

Hmm not sure, i don't know what exactly each valve is just the general understanding of the setup (Dammit Jim i'm an engineer not a scientist/plumber ). The pipe comes along under the floor and though a Ajax? valve to a ball valve which i thought was for draining, then up through the floor and loops up and back down to another ball valve and then into the bottom of the cylinder. I will try and remember to take a photo next time i am down there.

It did make me wonder later if i could turn off the water pump and open a hot tap to let the air in and then drain it from that "drain" valve?  Only problem i could see is the loop up in front of the cylinder would only let the water get down to about 1/4 full.