How Possums, Rodents, and Birds Get into Your Water Tank - and How to Keep Them Out

When thinking about water quality, most people focus on filtering out contaminants like sediment and debris.

But one of the most alarming sources of contamination often comes from something you might not expect – rodents, possums and birds entering your water tank.

At Safe H2O, we’ve seen first-hand how common (and dangerous) this problem can be, especially during dry seasons when animals are desperate for water.

In this blog, we’ll explain how animals get into your tank, the damage they can cause, and how you can prevent it – plus how Safe H2O can help restore your water supply if something does get in.

What Rodents (and Birds) Commonly Get Into Water Tanks?

A range of animals can find their way into rainwater tanks, including:

• Mice and Rats – Small and agile, these pests can squeeze through small gaps in pipe fittings or tank lids as well as via downpipes.
• Possums – Often accessing downpipes from your roof to find water or they can fall/climb into open or poorly sealed tanks.
• Birds – Birds nest in gutters or downpipes and they and their debris (feathers, droppings, hay/nest supplies) can be flushed into tanks. They can also chase insects into tanks that are not airtight.
• Other Wildlife – While less common, frogs and insects like mosquitoes, can end up contaminating your supply.

Unfortunately, these animals usually don’t survive once inside the tank. And dead animals left undetected in the tank water can pose serious health risks.

How Do They Get In?

Rodents and birds are persistent when they’re thirsty. Common entry points include:

• Downpipes from gutters – Especially if they’re not screened or fitted with deterrents like gutter whiskers.
• Cracks in tanks or fittings – Rodents can exploit even the smallest gaps.
• Unsealed, poorly sealed or missing tank lids – An open invitation for animals seeking water.
• Disconnected or poorly connected inlet or outlet pipes
• Non-screened inlet or outlet pipes
  

In summer, when surface water becomes scarce, these entry points are even more at risk as thirsty animals intensify their search for hydration.

Insects can also enter your tank through similar means and/or from eggs laid in stagnant water in gutters being flushed into your water tank.

They in turn can provide an added incentive for birds to enter the tank if they are not airtight.

What Happens When an Animal Dies in Your Tank?

The dangers aren’t just unpleasant – they can be seriously harmful to your health. Dead animals decompose quickly in water, causing:

• Bacteria growth – Including dangerous pathogens like E. coli.
• Bad tastes and smells – Decomposing organic matter changes your water’s odour and flavour
• Health risks – Drinking or using contaminated water can lead to gastrointestinal illness or infections.
• Clogged plumbing and pumps – Bones, fur, and feathers can block pipes and filters, leading to costly repairs.

Even if the animal is removed, bacteria and residue can remain in the tank unless properly cleaned and filtered.

How to Prevent Animals from Getting into Your Tank

The good news is there are effective ways to keep rodents and birds, as well as insects, out of your tank. Here are some of the key steps we recommend:

Seal the Tank

• Make sure your tank lid is secure and tightly sealed.
• Inspect for and patch any cracks or gaps in the tank body or pipe fittings.

Install Physical Barriers

• Use mesh screens or tank inlet filters to prevent pests from slipping in through downpipes or inlet/outlet pipes.
• Install gutter whiskers (at least on your downpipe entry) to minimise the risk of nesting birds and/or thirsty animals getting into the tank and stop leaves from clogging your gutters (we can supply and install these for you).
• Install first flush or leaf diverters on downpipes to prevent large debris from entering your water supply. During rainfall, you can open the flush cap to release the initial runoff, helping to keep contaminants that have accumulated on your roof from reaching your water tank.

Maintain Your Roof and Gutters

• Reduces the risk of birds or their debris falling into your tank.
• Avoid leaving organic matter (like leaves or droppings) where it could wash into your water supply.

How Safe H2O Can Help

If you suspect (or know) an animal has gotten into your tank, don’t risk your health. At Safe H2O, we can:

• Safely remove the animal and clean your tank thoroughly.
• Filter and treat your water to remove bacteria and debris.
• Inspect your system and alert you to any vulnerabilities we see while onsite.
• Supply and install gutter whiskers and offer advice on best practices for ongoing tank hygiene.
• Supply and install a UV filtration system to help remove sediment and neutralise bacteria before the water enters your home’s plumbing (even when harmful contaminants are present in the tank).

Our tank cleaning process is designed to preserve your water, where possible, while restoring it to a safe, usable state – protecting your health, without the guilt or cost of wastage!

Final Thoughts

Rodents and birds in your tank aren’t just gross – they’re dangerous. But with the right preventative steps and regular maintenance, you can protect your water supply and your health. Prevention is the best solution!

If you’re unsure about the condition of your tank, or it’s been more than two years since your last clean, it might be time for a professional inspection and service.

Need help now?
Book a professional water tank clean with Safe H2O today and enjoy peace of mind knowing your water is clean, safe, and animal-free.

👉 Contact us now to get a quote.