Like and Follow Us on Facebook


Are poly tanks safe to drink the water from? I’ve heard terrible things about BPA in plastic.

Poly (Polyethylene) tanks don’t use BPA (Bisphenol A) in the manufacturing process. Slim Thin Tanks source our tanks from manufacturers who use food grade polyethylene to ensure the tanks are safe for household use. Our manufacturers also comply with AS/NZS 4020:2005, Testing of products for use in contact with drinking water. We recommend utilising a filtration device before drinking water from the tanks and periodical tank/gutter maintenance is required to minimise contaminants entering the tank. Testing and treating the tank water so that it is adequately chlorinated will help reduce the contaminants in your tank.

What size tanks can you supply me?

When we talk about the capacity of slimline tanks, they can be as little as 350 litres through to 3000 litres in polyethylene tanks. Some of the tanks can be linked together with pipework to increase the overall capacity available to utilise. The shape of the tanks can vary from round, oval to rectangular depending on the manufacturer.

When we talk about dimensions, the tanks range in width from 260mm through to 800mm. Length and height are all dependent on the capacity of the tank, so there is an extensive range to choose from to suit an under-eave application. There is enough room under a standard single-story house to fit most slimline tanks and pipework.

What size tank do I need?

This is one of the most frequent questions we get asked and my first response is always what do you want to do with the water?

Using it to water the garden is a common answer.

The fact that this activity is more likely to be over the warmer summer months, having as much capacity as you can will counteract the time between the next rain to top up the tank. The Water Corporation of WA restricts our flow rate out of the mains to 20 litres per minute. So, every 10 minutes you’ve hand watered with the garden hose you’re using 200 litres of water. If you hand water every second day then you use 700 litres per week, just to give you an idea. This means 3000 litres of water can easily be used to keep your plants hydrated each month.

I want to keep my pool topped up over the summer.

With high evaporation rates and kids on school holidays splashing about, summer is high demand time for pools needing to be topped up. Utilising pool covers will help slow down the evaporation rate, but it won’t stop it. If you currently top the pool up for 10 minutes each day, then 200 litres a day or 1400 litres a week is going in to the pool. Saving water for topping up the pool requires a reasonable amount of storage, coupled with water saving tips and water efficient filters it all helps. The increase in summer storms in recent years has helped our tank levels over summer.

Can I use the water for my laundry/toilet?

This has become quite common with homeowners wanting to do their bit to conserve water and reduce the demand on scheme water. With dual inlet pump controllers, connecting to a tank and the mains for backup at the same time provides a continual supply to the home. This is the most efficient use of a rainwater tank as the water is continually being used in the high demand areas over the entire year. Some developers are even offering incentives to new homebuyers to install a rainwater tank connected to the house via a plumbing loop.

What colours do the tanks come in?

Each manufacturer has their own colour selection to choose from which can differ slightly from one to another. The colour charts are a guide only and the actual tanks will closely match the chosen colour. Please refer to the supplied colour charts or contact us for more information on availability.

What is a first flush diverter, and do I really need one?

The purpose of a first flush diverter is to collect the debris from the flow of water that runs out of your gutter when it first starts to rain. An internal float will rise as the chamber fills with water and debris and when full will divert the water across in to the tank. The size of the chamber will determine the amount of water that will be flushed to remove sediment and particulates that have gathered in your gutter between rain events. There is a drip valve that drains the chamber slowly so that the chamber is empty for the next time it rains. Keeping your gutters clean and regularly cleaning the drip valve on your first flush diverter helps to keep sediment from reaching your tank.

If you want to keep as much sediment out of your tank as possible, a basic first flush device is a cost-effective way of doing it. The cleaner you keep the water going in to the tank, the less build up you get over time to have to clean out. There are several types of first flush devices on the market to suit your needs and budget. Contact us for more information specific to your requirements.