Health Risks With Blocked Drains

Having blocked drains is a hassle we all dread. It’s smelly, unsightly, stressful and usually means an interruption to our day-to-day activities. But did you know that blocked drains can also be a hazard to your health?

What is a blocked drain?

When we talk about blocked drains, we’re referring to a group of plumbing problems. These may include:

  • blocked kitchen sink
  • blocked bathroom sink
  • blocked laundry sink
  • sink draining very slowly
  • blocked shower drain
  • blocked toilet or toilet overflow
  • blocked outside drain
  • gully trap overflow

So, it’s not just a clogged sink or toilet. A blocked drain essentially means a block in the way the water is draining from your property – whether that’s the kitchen, bathroom, laundry, etc, and it can be the sink, shower, washtub, etc. We refer to it all collectively as blocked drains.

What causes a blocked drain?

A blocked drain can be caused by a number of things:

  • substances going down the drain that shouldn’t be there (too much oil or grease, too much toilet paper, too much hair, etc)
  • your pipes or plumbing work may be old and worn, or not functioning safely
  • there may be something stuck in the pipes or plumbing work

We encourage you to read our article on How to Prevent a Blocked Drain for more information on how to prevent a blocked drain.

Possibly hazards and health risks from a blocked drain

As well as being smelly and a nuisance, a blocked drain can also be a health hazard and the cause of health risks in your home. That is because drains are actually quite unhygienic and loaded with germs. Think about what you wash down the sink, shower or drain. We wash down the drain dirt from our clothes and shoes, dirt from our hands and bodies, bodily fluids, toothpaste from our mouths, bacteria from cutlery that has been in our mouths … on the list goes on. In addition, when we put food scraps down the sink into the waste disposal unit, we’re creating a breeding ground for bacteria if we don’t wash it all down thoroughly.

All of that is completely normal and usually safe. Where the possibility for health risks comes in is when that dirty water doesn’t go down the pipes fully or when our hands come into contact with any of the bacteria present or the dirty water. When your drain is blocked, there is a high chance that grey water will come back up and you’ll come into contact with it. Even worse, if your toilet backs up and overflows, you run a high risk of coming into contact with water full of bacteria, germs and viruses.

Bacteria grows and multiplies in moist areas, so any water sitting in blocked drains or sewage pipes may harbour things like Salmonella, Campylobacter, E. Coli or Staphylococcus. Bacteria from raw meat is often found in a sink, and traces of faecal matter are often detected in showers and sinks. So it’s important to not only wash your sink and shower areas thoroughly, it’s also essential to make sure your drains are clearing effectively to reduce the risk of these bacteria spreading and causing you to get sick.

There is also the theory that some bacteria can become airborne and affect the air quality (not just the water quality) of a home. In these instances, people with asthma, hay fever, eczema and allergies triggered by air quality may suffer worse symptoms when there are blocked drains.

How can you prevent these health risks?

There are a few things you can do yourself to unblock a drain, before calling out a professional plumber for drain unblocking. It’s important to try to remedy the problem as soon as it happens to minimise any health risks that may result from a blocked drain. Have a read of our article on How to Unclog a Blocked Drain for a few tips and tricks. In another Sumich Plumbing blog, we also provide you with a list of reasons why your toilet might be getting blocked and how to prevent it.

If you need further assistance, we’re always happy to help. A well-maintained home is a healthy home.

Give us a call and let us help keep you and your home safe and healthy.


There are a number of plumbing and drainage companies in Auckland, so why choose Sumich?

Founded by owner-operator Chris Sumich in 1991, Sumich Plumbing & Drainage has one of the most experienced teams operating in Auckland. Our team has a combined experience of over 100 years and we’ve seen a comprehensive range of scenarios and solutions over the years. Clients trust us to give honest, transparent advice and service.

As registered members of the New Zealand Plumbers, Drainlayers & Gasfitters Association, we are professional, licensed Auckland plumbers for all of your plumbing, drain laying, gasfitting and heating needs. Give us a call to see how we can help.