How to keep your rainwater tank clean

Do rainwater tanks need cleaning?

Water tank cleaning can be an expensive and wasteful endeavour. Not only do you usually have to hire a professional so that you don’t cause any damage to your storage tank, you often have to dump your entire water supply and start again with clean water. This means either having to fill your rainwater tank from scratch and relying on mains water in the meantime, or paying a water carting company to come and fill your tank with clean water.

If you are simply using a rainwater tank for gardening or in the laundry, then you may not be as concerned about how clean your water storage tanks are, but if you’re looking to use the water in the home for drinking and showering, maintaining a clean water tank will likely be something you are concerned about.

Do rainwater tanks need cleaning if you take steps to keep your tank clean? Unfortunately, there’s not a simple cut and dry solution, but if you can prevent debris and sediment from entering your rainwater tank in the first place, the chances of having to fork out money to have tank sludge professionally removed by a tank cleaning professional are much lower.

Considering that the price of a steel rainwater tank is already a significant investment, it is smart to keep the ongoing costs as low as possible. So, in order to prevent any harmful bacteria or contamination from entering your tank, requiring you to have someone come and clean sludge or bacteria from your water supply, let’s have a look at some preventative measures.

Keep your rainwater harvesting system clear of potential risks

Your tank water is only as clean as the water that enters it, and a good first step is to ensure that your rainwater harvesting system is clear of leaves, dirt or any contaminants as often as you can.

First, ensure that you have removed any overhanging branches, as this is the most direct way that your rain gutter systems will end up full of leaves and twigs. Regular maintenance of any overhanging vegetation is important.

Regular cleaning and maintenance of your catchment areas is an important part of your water harvesting operations, and will help to ensure any leaf litter or organic matter don’t end up in your drinking water. It is recommended that you clean gutters and catchment areas at least four times a year including after any prolonged dry periods.

A way to take some time and effort out of this part of the process is to install a gutter guard, which will prevent larger debris like leaf litter from entering the gutters regardless of wet or dry periods. When installing a gutter guard it is important to ensure you’re buying one that isn’t letting too much debris through the filtration system, and that it is easy to remove for cleaning.

Catch any organic matter that may have slipped through

These first steps are the ones that will arguably have the greatest impact when it comes to keeping water tanks clean. However, they’re not the only ways of ensuring that dirty water doesn’t make it into your stored rainwater.

After a longer dry period of one or two months without any significant rain, accumulated sediments that have built up in your gutters or rainwater harvesting system will be washed away and into gutters and downpipes.

Understandably, it is a good idea to prevent this dirty water from entering your rainwater tank, and a popular way to do this, with minimal water loss, is to install a first flush diverter.

First flush diversion systems come in a variety of models and styles, however, they all have the same basic principle – to prevent the first few litres of rain after a dry period from entering otherwise clean water tanks.

This water can be flushed into gardens for irrigation, or into greywater systems so as to still use the water sustainably while keeping the build-up of sediment out of your stored rainwater.

Other systems that can work in support of this are filters that can be fitted to any downpipes leading from gutters, and even more high tech water filtration systems that can be fitted to tank inlets as a last line of defence.

These however are often passed over in favour of leaf filter baskets and lids, which typically catch most remaining leaves and other sediment. Leaf filter baskets should also be inspected for cleaning, occasionally, checking to see if they’ve been filled with leaves or sticks.

Keep the stored water clean

Once you’ve got clean water in your tank, it is important to ensure it stays clean. A steel, Colorbond® or Zincalume® will prevent any light from entering the tank and fostering bacteria growth.

Installing a seal around the top ring of a steel tank is important to keep out any vermin or insects such as mosquitoes. These seals are relatively simple to install, and fill the small gap at the top of water tanks with a durable and dense foam.

Pioneer Water Tanks in Brisbane offers a product called the Superseal as a standard accessory – whilst in other states, it is optional – simply due to the importance of this added layer of protection in the state of Queensland.

This will keep your rainwater supply free of any unwanted organic matter, and ensures that your other efforts to keep your rainwater tank clean weren’t in vain.

What if you’re still not confident?

If you’re still not confident in your tank water – though state governments recommend that rainwater is safe for drinking, despite not containing the chlorine or fluoride content of town water – there are final steps you can take.

If your tank requires a pump, you can have a filtration system fitted after the pump as part of the plumbing to the house to keep the last amounts of dirt or sludge from coming up the pipes. Cleaning this filter on a semi-regular basis is also a good idea if installed.

As a final step, which you may even have fitted if you’re using mains water or town water, you can fit a water filter to your kitchen tap, to catch any last particles from entering your food preparation and drinking water.

So, do rainwater tanks need cleaning? They still might, as tank cleaning can be unavoidable due to the nature of tank water and harvesting rain from rooves and gutters. However, the likelihood of having to pay for cleaning – potentially wasting precious rainwater supply and having to pump new water in – is greatly decreased by a proactive response to rainwater harvesting.

So get out there and fill those tanks with fresh, healthy rainwater, without the stress of water tank cleaning weighing too heavily on your mind.

Jack Turner
Jack Turner
Jack Turner is a content creator for the Australian water storage company Pioneer Water Tanks. While he now lives in the city for his job, he grew up in rural Western Australia and remains a country boy at heart.
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