Ants living in your hot water system? Should you be concerned?

ants living in hot water heater

What to do if you’ve got ants in your hot water heater.

While most people may think ants are harmless creatures that can’t cause a lot of damage – we disagree. We regularly encounter hot water heater problems that are a result of these tiny little creatures.

We were recently called to a Rheem hot water repair job on Sydney’s Northern Beaches where the customer awoke to no hot water.  He was blissfully unaware that an army of ants had been living in his hot water heater for months. The movement and ant’s waste had caused the thermostat to short and the water stopped heating.  We had a suitable Rheem thermostat replacement part in the truck and the customer was enjoying hot water again within a couple of hours.

Common hot water heater problems caused by ants

Most hot water heaters are warm and dry – an irresistible environment for ants to live safely and undisturbed.  The two most common problems ants cause when living in a hot water system include:


The ant’s movement and refuse can cause parts to short out and cease working.


Inside almost all hot water tanks is foam insulation.  Often made from polystyrene, this foam reduces heat loss thereby improving the water heater’s energy efficiency and saves money. Ants often eat through this insulation causing “holes” in the thermal lining, thereby losing thermal efficiency. If you open the access panel (usually at the bottom of the hot water heater) you may notice a sand-like substance at the bottom of the tank.  This is usually a mix of the thermal insulation, ant refuse and nesting material. See photo below.

ants living in hot water heater
Evidence of ants living in an outdoor hot water heater.

Preventing ants from entering your hot water heater

There are a few simple steps you can follow to prevent, or dissuade, ants from nesting in your hot water tank.

While we are not professional pest controllers, we recommend customers try spraying around the hot water heater with an insecticide.  Safe, non-pesticide alternatives include lavender and peppermint oil (ants don’t like these scents). These methods create a barrier and help discourage ants from entering the water heater.

When we install a new hot water heater that has previously been affected by an ant infestation, we implement insect-proofing measures. These included sealing any potential entry points and applying deterrents to discourage ants from making their way into the new hot water heater.

ants short circuited hot water system
Ant infestation caused this solar hot water backup system to short-circuit and stop working.

Did you know your hot water heater should be serviced every 5 years?

A regular service by one of our authorised hot water repair technicians will ensure you enjoy trouble-free hot water for many years to come.  It is during a hot water service that we often discover the presence of ants – much to the customers surprise.

A regular hot water service ensures your system continues working safely whilst increasing the cylinders longevity, therefore saving you both money and inconvenience of future breakdown.

Your hot water service should be undertaken by a licensed hot water plumber no longer than every five years. If this time period lapses it may result in the manufactures warranty becoming void. It doesn’t take long for a technician to service a system – usually between 30 to 45 minutes. It’s a small price to pay for peace of mind and trouble free hot water usage.

Did you know that most manufacturers won’t cover the terms of your hot water system warranty if it isn’t installed or serviced by a licensed hot water technician or qualified hot water plumber. Hot water tanks are an expensive appliance so why would you risk voiding your warranty by installing it yourself or employing the services of someone who isn’t licensed?

We are licensed water heater installers and plumbers and preferred service technicians for all major hot water manufacturers including RheemSolahart, Rinnai, Dux, Aquamax, Apricus, VulcanEdwards Solar, Everhot and many more brands.

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Hot water is our business! We are your local hot water service specialists covering all Sydney suburbs and the Central Coast.  Our trucks are on the road right now, filled with thousands of spare parts and replacement gas, electric and solar systems to ensure you’re back enjoying hot water today.

The information on this website is of a general nature only. We do not make an warranties about the completeness, accuracy or reliability of this information or whether it is relevant to your specific hot water problem(s). For professional hot water repair advice specific to you, contact our Sydney hot water specialists direct on 0410 693 532.

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