A rainwater tank is one of the lowest-maintenance bits of gear on any property, but “low maintenance” isn’t “no maintenance.” A few simple checks through the year keep your water clean, your system working properly, and your tank lasting the distance.

Here’s the good news: most of what matters takes minutes, not hours, and you don’t need a trade ticket to do it. This guide walks through what to check, how often, and why it matters, so you can get the most out of the water you’re storing.

How often should you check your rainwater tank?

For most properties, a quick once-over every three months is plenty, with a more thorough look heading into the seasons that matter most for your setup, before a dry stretch if you rely on the tank through summer, or after heavy leaf drop in autumn.

Think of it in three layers:

•     Quick visual check (every few months): Glance over the inlet, strainer, overflow and fittings. Two minutes.

•     Seasonal check (a couple of times a year): Clear the strainer and gutters, check your water level, look over the hardware properly.

•     Deeper clean (every 2–3 years, or as needed): Check sediment build-up inside the tank and arrange a clean-out if required.

The exact rhythm depends on your surroundings. A tank under heavy tree cover collects far more leaf litter than one in the open and will need the strainer cleared more often. Let your own property guide how often you look.

Keeping your rainwater clean

The quality of the water in your tank comes down to one simple idea: what goes in is what you store. Most water quality issues start at the inlet, not inside the tank, so that’s where your attention pays off most.

Clear your gutters and downpipes

Leaves, twigs and grit sitting in your gutters get washed toward the tank with the next decent rain. Keeping gutters clear is the single most effective thing you can do for clean tank water. It’s also worth checking that downpipes are flowing freely and not blocked.

Check your leaf strainer and inlet

Your tank’s inlet strainer is the first line of defence, it catches debris before it reaches the water. On RapidPlas tanks, this is the strainer with a light and dust cover, designed to keep leaf litter out and block sunlight (more on why that matters below).

Lift the cover, clear out anything that’s collected, give it a rinse if needed, and make sure it’s seated properly when you put it back. A strainer that’s clogged or sitting askew either lets debris through or causes the inlet to overflow and waste good water.

Make use of a first-flush diverter

A first-flush diverter sends the dirtiest initial runoff, the water that’s picked up dust, bird droppings and debris off your roof, away from the tank before clean water starts flowing in. If you’ve got one fitted, check that it’s draining and resetting properly so it’s ready for the next rain. If you don’t have one, it’s a worthwhile addition for keeping stored water cleaner.

Preventing algae in your tank

Algae needs two things to grow: sunlight and warmth. Take away the light, and you take away the problem.

This is why a properly fitted, light-blocking inlet cover matters, and why poly tanks are made in colours and materials that block light from getting through the walls. Keeping your tank sealed against light is the best algae prevention there is.

A few quick pointers:

•     Make sure all inlets, the strainer cover and any access points are properly covered and sealed against light.

•     Check that insect screens and covers are intact, gaps let light in and pests through.

•     If you ever notice algae, it’s a sign light is getting in somewhere. Track down the gap rather than just treating the symptom.

A quick word on chemicals: you don’t need to be regularly dosing your tank with chlorine, bleach or copper sulphate to keep algae at bay. If light is properly blocked, algae can’t grow in the first place, which is a far better approach than treating it after the fact.

Do you need to treat or filter your rainwater?

For most uses, well-stored rainwater is good to go straight from the tank, and that’s part of the appeal. Rainwater collected and kept clean is a naturally soft, fresh water source, without the added treatment that goes into town water. The trick is to match how you treat the water to how you’re using it.

No treatment needed for the bulk of what most properties use tank water for, watering the garden and lawn, washing the car, hosing down, toilets and laundry. Clean, stored rainwater handles all of this without anything added.

Filter at the tap if you’re drinking it. If you’re using your rainwater for drinking or cooking, the sensible approach is point-of-use filtration, filtering the water as it comes out, rather than treating the whole tank. A good filtration setup deals with anything you’d want removed before it reaches the glass, while leaving the rest of your supply untouched for everything else. (Our guide on how rainwater filtration systems work walks through the options.)

The takeaway: keep the stored water clean by design, block the light, screen out debris and pests, divert the dirty first runoff, and add filtration only at the point where you need drinking-quality water. That’s cleaner, simpler, and cheaper than dosing a whole tank.

Knowing your water level and managing reserves

You can’t manage what you can’t measure. Knowing how much water you’ve actually got in reserve is the difference between planning ahead and getting caught short, particularly heading into the drier part of the year.

If your tank has a dial gauge or level indicator, get into the habit of checking it. If you’re still guessing by tapping the side of the tank and listening for the hollow note, it’s worth fitting a proper dial gauge or one of the other accessories that make a tank easier to live with, so you always know where you stand at a glance.

Managing reserves is mostly common sense: know what you’re using, know what’s coming in, and keep an eye on the gap, especially when rain is less reliable. If you’re regularly running low, it may be a sign your storage capacity isn’t matching your needs.

Image A: Dial Gauge Level Indicator

Image B: Rapid Smart Level Indicator

Image C: Water Beacon Level Indicator

Checking the hardware: outlets, valves and overflow

A slow leak is water you can’t afford to lose, and the kind of thing that’s easy to miss until your level drops faster than it should. A quick check of the hardware a couple of times a year keeps everything working as it should.

•     Outlets and valves: Check the BSP outlets, ball valve and any fittings for drips or seepage. Tighten or replace washers as needed.

•     Overflow: Make sure the overflow outlet is clear and directing excess water where you want it, away from the tank base and footings, not pooling underneath.

•     Pump and connections (if fitted): Check pump fittings and connections for leaks, and make sure the pump is running cleanly. Refer to your pump’s own manual for its maintenance schedule.

Checking the tank itself

Tanks are built to be left alone, but a quick look over the tank and its surroundings is worth doing:

•     Around the base: Clear away leaf litter, soil build-up or vegetation against the tank. Keeping the base clear helps prevent moisture sitting against the tank and keeps the area tidy.

•     The stand or pad: Make sure the tank is sitting level and the base or pad is sound. Tanks are heavy when full, and a stable, even foundation matters.

•     The tank walls: A glance over the outside for anything unusual. Quality poly tanks are UV-stabilised and built to handle Australian sun, but it never hurts to keep an eye on the general condition.

Cleaning the inside of your tank

Over time, fine sediment settles to the bottom of any tank. In most cases this sits harmlessly below the outlet and doesn’t affect your water, which is why a properly maintained tank only needs an internal clean every few years, if that. (If you’re storing water for long stretches between top-ups, it’s worth understanding how long rainwater keeps and what helps it stay fresh.)

When sediment does build up enough to need attention, you’ve got two options:

•     Self-siphoning / desludging: Some build-up can be drawn off the bottom without fully emptying the tank, using a siphon method.

•     Professional clean: For a thorough job, professional tank cleaners can clear sediment and clean the interior properly. This is the safest option for larger tanks.

A note on safety: large tanks are confined spaces. Never enter a tank to clean it without the proper training and equipment, it’s genuinely dangerous. For anything beyond a simple siphon from the outside, call a professional.

When to DIY and when to call someone

Most rainwater tank maintenance is well within reach of any property owner, clearing strainers, checking levels, looking over fittings, keeping the base tidy. That’s the regular stuff, and it’s easy.

Call in a professional for:

•     Internal tank cleaning on larger tanks

•     Anything that involves entering the tank

•     Plumbing or pump issues you’re not confident tackling

•     Concerns about the tank’s structural condition or foundation

There’s no prize for taking on a job that’s better left to someone with the right gear.

Your quick rainwater tank maintenance checklist

A simple run-through you can come back to:

Every few months

•     Glance over inlet, strainer, overflow and fittings

•     Check for any obvious leaks or drips

A couple of times a year (seasonal)

•     Clear gutters and downpipes

•     Clean the leaf strainer and check the cover is sealed

•     Check the first-flush diverter is draining and resetting

•     Check your water level / gauge

•     Look over outlets, valves and overflow for leaks

•     Clear debris from around the tank base

•     Confirm the tank is sitting level and the base is sound

Every 2–3 years (or as needed)

•     Check internal sediment build-up

•     Arrange a professional clean if required

 

Frequently asked questions

Quick answers to the questions we hear most.

How often should a rainwater tank be cleaned?

A quick visual check every few months and a proper look a couple of times a year covers most maintenance. The inside of the tank usually only needs a sediment clean every 2–3 years, depending on your setup and surroundings.

Do I need to put chemicals in my rainwater tank?

No. If your tank is sealed against light and debris, algae can’t take hold and you don’t need to dose the water with chlorine or other chemicals. For drinking water, use point-of-use filtration rather than treating the whole tank.

Is rainwater safe to drink straight from the tank?

Well-stored rainwater is fine for the garden, laundry, toilets, washing and most household uses straight from the tank. If you want to drink or cook with it, fit a point-of-use filtration system. If you’re ever unsure about your water quality, speak to a qualified professional.

How do I stop algae growing in my tank?

Block the light. Algae needs sunlight to grow, so a light-blocking strainer cover, sealed inlets and an opaque tank are all you need. No light, no algae.

A tank built to last makes maintenance easier

Good maintenance keeps any tank in shape, but it starts with a tank that’s built properly in the first place. A quality, UV-stabilised poly tank with a well-designed inlet, a light-blocking strainer cover and solid fittings as standard simply needs less looking after than a cheaper alternative that cuts corners.

At RapidPlas, every tank is made to order in Tamworth, tested to exceed Australian Standards, and built tough to last in real Australian conditions. Our tanks come standard with the features that make maintenance straightforward, including the leaf strainer with light and dust cover that keeps your water cleaner and helps prevent algae from day one.

If you’ve got a question about caring for your RapidPlas tank, or you’re thinking about adding to your water storage, our team is always happy to help. Give us a call on 02 6765 0700, we deliver from Bega to Bundaberg, and we’re here for the long haul.

Related reading

•     How Rainwater Filtration Systems Work — Clean Water for Your Home and Garden

•     Can I Store Rainwater for Long Periods? Here’s What You Need to Know

•     What Can Go Wrong With Poly Rainwater Tanks

•     What Makes a Quality Rainwater Tank: Features to Look For

•     What Are the Best Rainwater Tank Accessories?