Take advantage of spring’s usual wet weather and set up a rain collection system so you can give your garden free water. They say you should make hay while the sun shines. Well, in this case, catch it while you can – the rain that is. Take advantage of spring’s usual wet weather and set up a rain collection system so you can give your garden free water in the hot, dry months of summer.

Rainwater collection need not be expensive, and here is a simple DIY method to set up your own system in time for summer. In addition, you will have access to water in case of Civil Defence emergencies. Urban rainwater is generally not used for drinking because of pollution, but filtering or boiling will provide a handy resource, a lesson we can take from Christchurch’s experience.

To build a DIY barrel water collection system you will need:

• Lightproof containers in which to store your water. If you go for recycled plastic barrels ensure they have not been storing toxic substances. Ideally, find barrels used by the food industry, then you know they are safe. Connect as many as you like that will fit in the space you have available. The more capacity the better – you’ll be surprised how much water your garden will soak up in summer.

• A rainwater diverter. A hose connection plus tank connector between diverter and drum. Go for a 20mm diameter hose to catch the most water during light rainfall.

• A plastic tap. One of 20mm diameter works with standard garden fittings, but check with your supplier. Brass taps require mains pressure, so aren’t ideal for small tanks.

• Link your barrels with 15mm tank connectors and sections of garden hose.

• Materials to build a tank stand. Concrete blocks are easiest, or build a sturdy, braced timber stand.

• Metal strapping and long screws to secure your barrels to a wall or structure. Ensure it is all child-safe.

Location

Put your barrel near a downpipe on your house or garage.

Sturdy footings

Build a stand on level ground, ideally a hard-paved surface. The easiest is to stack two layers of concrete blocks. Dig out any unstable topsoil and replace with compacted fill or pavers. Make sure you can fit a watering can underneath. A good plan is to find a spot higher than your garden so you can get some water pressure.

Connecting the tap

If you wish to attach standard garden fittings to your barrel, choose 20mm inlet and outlet connections. With a 26mm “flat bit” drill attachment on your power drill, make a hole for the tap 40mm from the base of your barrel.

It is easier to secure the tap from the inside if you have a lidded barrel, but often recycled ones have a bung and no lid.

Unless you have a very long arm you will need to use the following trick to get the tap components down to the right spot. Thread a weighted string through the connector (head to tail).

Drop the line inside the drum and through the hole. Slide the connector down and through the hole. Replace the nut and washer.

Cut off the barbed end of the connector for a standard tap connection. Connect your tap from the outside, winding it up tightly.

Connecting multiple barrels

The barrel connectors should be about the same level as the tap. Drill a 20mm hole with a flathead drill bit for a 15mm connector.

Use the previous technique but retain the barbed ends when you install the 15mm tank connectors between drums and push your hose on to the barbed end of the connector.

Water inlet

Some closed-head barrels are fitted with a threaded insert in the bung. Simply take it out and fit with a 20mm hose tail. Otherwise, you can drill a hole through the centre of one of the bungs, then install the hose tail with the aid of a lock-nut. A 20mm pipe requires a 26mm diameter hole.

Connect the diverter to your downpipe

Put the barrel on the stand to find the correct height to locate your diverter on the downpipe. With open-top lidded barrels it is important that the internal overflow of the diverter is the same height as the final water level of your barrel at the top. Once the water reaches this level, it will overflow back down the diverter and into the downpipe and ultimately the stormwater system.

With closed-head barrels the diverter can be installed at any height as long as it is above the barrel. Follow the instructions that come with your diverter to install it correctly. This is usually quite simple and involves cutting a segment out of your downpipe and inserting the diverter in its place.

Make it child-safe

Finally, secure the barrel in place so a child can’t accidentally pull it down when it’s partly full. Use metal strapping and screw to the wall or structure behind. Also ensure that lids on open-top barrels are fastened securely.

Suppliers

Barrels, water butts, diverters and complete range of fittings: Rainworks/Hedgehog www.hedgehog.cc; Rainline www.rainline.co.nz

Barry’s Barrels www.bb.net.nz

Parts: tank connectors and taps: Chesters or other plumbing trade suppliers

Urban tank styles: retro corrugated tanks in traditional and slim profile www.tanksalot.co.nz; slimline tanks www.thintanks.co.nz; www.newwater.co.nz

A certified plumber can connect a large rain tank for non-potable water use in your house (toilet and laundry) to save even more money on your water bill, particularly over winter when you don’t need to water the garden.

More info Laurie Dee at Rainworks/Hedgehog, on www.hedgehog.cc is happy to help.

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• Thanks to Laurie Dee for helping with the technical details in this article.

– Written for the Herald on Sunday by Meg Liptrot.  Image / Meg Liptrot