my toilet is leaking brown water!

Help! I Have a Toilet Leaking Brown Water

When you have a toilet leaking brown water, it’s normal to think the worst.

Someone has either missed the bowl or the toilet is leaking contents that should be flushed away, and never seen again. No one wants to see what the toilet had for breakfast, lunch and dinner.

I was recently asked by a friend to check out her leaking toilet to see if it was something I could easily fix, without having to ring another plumber. The irony. Except it wasn’t because she didn’t trust my skills, it was simply because the house she lived in was a rental and it would be up to the real estate to contact the owner so they could organise their own plumber to fix.

leaking toilet with brown water

Plumbing issues in rentals can be a pain in the butt to deal with as it can be a waiting game for the owner to organise a plumber to fix.

Nevertheless, I headed out to see what was causing this brown water to leak from the toilet.

Thankfully, on inspection I could see immediately that it wasn’t waste water, despite its brown appearance. The leak was coming from the toilet cistern, which was being fed by a rainwater tank.

toilet leaking brown water, what is the cause the plumbette

Looks a bit suspicious…

Rainwater is notorious for turning brown over time which is caused by a sludge that builds up at the bottom of the tank. The sludge is caused from dust, bird droppings, dirt and whatever sediment settles on the roof which gets washed away by the rain and travels along the gutters and downpipe, where it gets caught into your rainwater tank. When it sits in the tank, it congeals to create a brown/black sludge and this is what can give tank water that brown colour.

It is recommended rainwater tanks should be cleaned every year, but it’s one of those household maintenance chores that is lost by the wayside as another thing to do. If your rainwater tank is used for drinking, it is IMPERATIVE to follow a maintenance routine or you will get sick.

For most domestic households in Australia, a rainwater tank is used for outdoor use or used to fill toilet cisterns, as was the installation at this rental house.

Because the toilet is a close coupled toilet, I couldn’t see where the leak was coming from inside the toilet, but my guess is it’s between the connection of the toilet cistern and pan – possibly the donut rubber seal may need to be replaced to stop the water running through the back of the pan. The waste pan collar was dry so I could confirm it definitely wasn’t waste water.

Whenever a leak like this occurs, it’s a good idea to get a plumber to fix it as soon as possible.

To remove the brown colour in tank water, your local irrigation store will advise on the right chemical that can be added to the water to control the bacteria and fungus in the water. The World Health Organisation recommends Chlorine Dioxide for drinking water, but for tank water that is used for cleaning outside or used to fill toilet cisterns, a different product may be recommended. I recommend Total Eden for water tank needs so check with them on the right approach.

Have you ever experienced a toilet leaking brown water? Or have you had a leak that has left you baffled?

If you enjoyed this post, here is another reason why you have brown water in your house.



  • We’ve had a few baffling plumbing situations in our house that have gone on a day or so because our real estate and their contractors are a bit slack at actually showing up to fix things.

    • Why am I not surprised to read this. Unfortunately it’s a universal issue and quite common. Hope they get sorted sooner rather than later. x

  • I am scared of brown water, every time! I’m glad it wasn’t a huge issue for your friend.

    • Yeah, brown water always looks suspicious. Especially when it comes from the toilet. 🙂

  • Alicia-OneMotherHen

    We have a filter after the pump on our rain water tank, and our water comes out crystal clear. We have it plumbed to the kitchen sink and only use it for drinking. We have never treated it though, and after reading that, I might look into it!

    • Ahh the filter should be fine on the water and help remove the impurities, but the tanks do need to be cleaned every year and may be more if you drink the water. In the case of this blog post, the tank water is used for toilet flushing and hose taps outside, not for drinking.

  • Hugzilla

    We had a new toilet installed last year so hopefully this is not something I will have to worry about for a very long time!

    • I hope so for your sake. Although I read recently you have yellow water all over your renovated bathroom. 🙂

  • Tracy

    One of our toilets started leaking from the side, at the base. Turned out it was the seal for the pipe that goes down into the floor. The plumber came out and had it fixed within an hour…and then he came back the next day to adjust the fall of the pipes under the house. And he reattached the cistern to the wall, and sealed the base of the pan to the floor.
    No more leaks. No more blocked toilet. No more running cistern. Best couple of hundred bucks I’ve ever spent.

    • Love this Tracy. What a great plumber to look underneath and restore your toilet so it was sealed and no longer wasted water. 🙂

  • Oh you’re so clever, Bec!! I know who to call if we ever get in strife with our dunny 😉 xx

    • Of course lovely. No call out fee for you darling. xx

  • You’re right, brown water does look a bit suss … glad it’s nothing too icky!

    • LOL. It does when it comes from a toilet. But this was all a ok. 🙂

  • When I was at boarding school, all the toilets overflowed into one massive leak in our dorm and it’s scarred me for life! I think I would have to call a plumber and shut the door and just use our other toilet instead! LOL!

    • Oh Sammie, overflowing toilets are not good. Sounds like there was a major blockage somewhere. Eww. x