If you spend about five minutes on YouTube or WikiHow, you’ll be convinced you can do anything via DIY. They have tutorials on everything from pronouncing foreign words to replacing toilets and moulding scented candles. Those videos and how-to’s make everything look really easy. What they don’t tell you is they probably shot the video in 73 takes and that editing is magic. With good lighting, the right music, and lots of splicing, everything looks do-able. The same applies to installing underground water tanks in Sydney.
The videos and articles make it look super simple. Just dig a whole, drop your tank in, and cover it up, hey presto! The reality is a little different. So yes, while it IS possible to put your own tank in, it’s not as straightforward as it seems online. Let’s look at some of the finer points you might need help with before you start something you can’t finish. After all, incorrect installation could cost a lot of money, and time too.
Pipes and plumbing
This is the bit that really needs an expert, and web tutorials are oddly quiet about it. They’ll be quite detailed on excavation and measurements, but then they’ll put one line about ‘calling a plumber to help install your gauges.’ Your underground tank needs a significant amount of plumbing work, both on the roof and under the ground. First, you need a system of roof gutters and down pipes to guide rain water into your tank.
It should include a run-off diversion mechanism so the first rain water doesn’t go directly into the tank. These first sheetsof rain will soak up the dust and debris on the roof, so you want it sent elsewhere, then the cleaner water can get into the tank. You also need a filter at the top of the tank to keep out leaves and surface debris, and a structure that prevents ground-level run-off from splashing into the tank.
Then you need water pressure gauges so you can check the level of water in your underground tank. You need a pump to push the water up, and a rain switch so your water supply can automatically convert from mains to the underground tank, depending on usage requirements and water levels. None of that can be done using a YouTube tutorial, so be sure to call in a roof plumber and electricals specialist for that portion of your installation.
Again, online guides just say ‘dig a hole’. But if your tank capacity is anything over 5,000 litres, you need a really big hole. Sometimes, the hole will reach the rock table. Other times, the soil is sticky clay or crumbly loam, and both are difficult to work with. You need a bulldozer (and someone that knows how to operate it). You might need some drills, possibly a few sticks of dynamite once your tank exceeds the 20,000 litre mark.
And this is before you have to level out the base and smoothen the sides of your tank hole. You can do this on your own if you have experience in the construction sector, but even there, those skills are fairly specialised. The crane driver doesn’t lay or cure concrete, so if you have one of those abilities, you’ll probably need to outsource the other. If your concrete tank is being poured on-site, you’ll also need a cement mixing truck.
Before excavating your tank site, you need permission from your neighbourhood council. They’ll tell you if there are any sewer pipes or utility lines to avoid, and if there are, you’ll need expert help doing so. If your yard has any mature trees, they may have to be extracted down to the root. Tree roots have destroyed house foundations, so image what they can do to your tank. And because it’s underground, you wouldn’t spot the damage until it’s too late.
The kind of tree that can break through concrete isn’t one you can lop on your own. Call in a consultant landscaper to advise you on the best approach. The last test of your ‘DIY skill’ is putting the tank in place. Polyethylene tanks and pre-assembled concrete tanks are slightly simpler than pouring concrete on-site. Still, your underground water tank installation requires precision. The tank will be positioned by crane, and if you’re not careful, the tank can crack and break on its way into the hole. The refilling process needs care as well. You have to pack in the filler carefully, and alternate back-filling with water-filling inside the tank. On your own, it could take hours to get the balance right, while experienced installers can do it much faster, so save yourself the drama and call the experts.