If you are ready to invest in water storage, the hard part is not finding a tank. It is working out which tank is right for your site. There is a lot to consider, and the first stage of the buying process can seem daunting, but the decision breaks down into a manageable set of pieces: how much water you need, what you can spend, where the tank will go, what it should be made of, and what looking after it will involve. This guide works through them in that order. If you would rather approach it as a list of questions to put to a supplier before you order, our buyers checklist covers that ground instead.
Size
We firmly believe bigger is better. No one has ever complained to us about having too much tank capacity, and you will always find ways to use that water. Droughts are becoming very common, and those once in fifty-year droughts seem to be happening every few years now. Being able to irrigate your property at the height of summer, and during council water restrictions, keeps your garden alive when nothing useful is landing on the roof. Maximising tank volume is a sensible response to extended dry spells, and it costs far less to do at the point of ordering than at any point afterwards. Work the number out properly with the rainwater tank size calculator rather than guessing it.
Budget
Budget will be a factor, but that does not mean you should buy a smaller tank just because it is cheaper. There is a small price differential between a 25,000-litre Promax tank and a 30,000-litre Promax tank, and that extra water is priceless. It is better to pay a little more and get enough capacity in one tank than to buy and install a second tank later when you realise you need more storage. If the budget genuinely will not stretch, do not forget our highly affordable XPRESS water tanks. They do not share the same features as our premium ENDURO corrugated tanks, but they are available in the same sizes, so you are not forced to trade capacity for price. The ENDURO and XPRESS comparison sets out what differs.
Location
The more space you have, the bigger the tank you can buy, and the more choice you have about where to place it. But even if you do not have acres of land, that does not mean you have to miss out on the benefits a Promax water storage tank gives you. New Zealand residential sections are shrinking, with large blocks subdivided into smaller ones, and our rectangular slimline tanks can slot into these tighter spaces. Whatever shape you settle on, think about access before you commit to a position. Just be sure you do not place the tank so that it impedes easy access around your house, because that is a problem you will notice every week for years, and a full tank is not a small thing to move.
Material
Naturally, we believe plastic is the best material, but we understand you have a choice. Concrete is one of your options. You can bury concrete tanks for aesthetic reasons, and they keep water cool because of concrete's high insulation value. On the downside, concrete tanks are heavy and difficult to install. It is not easy to retrofit new outlets to concrete tanks, and as rigid structures they lack flexibility and are prone to earthquake damage.
Promax plastic tanks are more flexible and can withstand earthquakes, while their light weight makes them easy to move into position and install. It is relatively straightforward to retrofit outlets on plastic tanks too. From a budget point of view, Promax tanks are generally cheaper to buy and install than their concrete counterparts. We compare the two directly in concrete or plastic: which water storage tank is best.
Repairs and Maintenance
Water tanks have been common in New Zealand for many years, and there is a whole industry devoted to repairing, maintaining and cleaning them. Polyethylene helps here: it can be welded, patched and repaired if required, so damage is usually a repair rather than a write-off. When it comes to cleaning, we recommend you use a professional tank cleaning company. They can vacuum the base of your tank without emptying the water, so you do not lose the storage you have spent months collecting. Alternatively, you could consider installing a Tank Vac, which removes the build-up of sediment already present and helps keep your tank clean all the time.
Material choice follows you into maintenance. Concrete tanks should be given a cement wash every few years to counteract the leaching of lime into the water. If you choose a plastic water tank, you will need to test the acidity of your water and plan how you will raise the pH if it is too acidic.
Council Consent
Only the council in your region can tell you whether you need building or resource consent to install a water tank. Requirements differ between districts and they change. Our team is familiar with the processes surrounding consents and, wherever possible, we will assist you based on our knowledge of these requirements. We welcome your questions and will give you as much guidance as possible, but the council will make the final decision on whether you need consent, and it is far better to ask them at the start than once the tank is on site. There is more detail in do I need a consent for a water tank.
Keeping the Water Clean
When you put in a new tank, think about how you will keep the water clean from the outset, because it is much easier than correcting it later. Contaminants on your roof will be flushed into the tank, and the first flush after a dry spell carries the worst of what has collected up there since it last rained. You should aim to minimise this by diverting that first flush of water away from your tank. There are many products that do this, or you can create your own. It is a small part of the overall budget with a disproportionate effect on what eventually comes out of the tap.
Talk it Through Before You Order
These are a few pieces to the tank buying puzzle, but Promax will make it an easy one to solve. Most of it comes down to being honest about your own site: how much roof you have, how much space, how much water you actually use, and how much maintenance you are realistically prepared to do. If you want a second opinion before you commit, our team works through these decisions every day and will tell you when the honest answer is that it depends on your site. Contact us for further information and advice to help you make the right decision. Call Promax on 0800 77 66 29.