South Africa is a dry country, even though it gets a lot of rain. This is because the country’s terrain isn’t ideal for capturing water. Luckily you can take matters in your own hands and have rainwater storage tanks installed. This is a very smart way to have extra water, especially if you are irrigating a garden or vegetable patch. Water storage tanks can be constructed from various different materials, so let’s look at the pros and cons for each:
High Density Polyethylene
Polyethylene is really just a fancy word for common plastic that is used around us every day. But it can be made very strong and molded in all kinds of shapes, without breaking the bank. So it’s no surprise that polyethylene water tanks are very popular and seen everywhere. A good tank will have UV protection. Overall such tanks are perfect for most situations – the only real complaint is that their fittings are not molded on, which might spring leaks if not maintained. It is also important that the tank uses non-toxic or ‘food grade’ polyethylene, else chemicals from the plastic can leach into the water.
Fibreglass is a very good material for water tanks. Highly durable, a fibreglass tank can outlast almost anything else on this list. So why don’t we all just use fibreglass tanks? Unfortunately fibreglass isn’t cheap, especially if the tank is quite small. It is most ideal if you require large tanks, particularly custom-designed ones. Another major benefit is that fittings can be molded on and avoid leakage (the downside being that you easily can’t replace the fitting). Fibreglass tanks should have an internal lining to reduce algae growth.
There are good reasons to place rainwater storage tanks underground: it saves space and the tanks last longer because they are not exposed to the elements. But ground brings its own challenges, since it expands and contracts. As such an underground tank must be reinforced or else it will rupture. Don’t just stick any tank in the ground, because you will regret it in the long run. Underground polyethylene tanks are designed to withstand the rigors of the soil. Just keep in mind that it will require a pump to successfully extract water from underground tanks, as they lie lower than everything else.
If you want a really charming touch, you can look at wooden tanks. These can be made from a variety of woods and are sealed by using a non-toxic plastic liner inside. But finding someone capable of building such a tank can be tricky. Wooden tanks aren’t cheap to build, plus they require regular outside maintenance to keep looking good.
Rainwater storage tanks made from metal, especially corrugated iron, are not uncommon. They are very resilient against outdoor exposure, not the least because they can contract and expand as required. A metal tank should still ideally have a non-toxic plastic liner or a layer of resin paint inside to seal it properly.
Concrete is one of the best materials to build a rainwater storage tank with. It will last very long, it can be used to create a wide variety of designs, and concrete also reduces the acidity of the water. The downsides are that where you place a concrete tank is where it will stay, not to mention that it can be more expensive. Such tanks are permanent structures and typically built to complement a building. If you are designing a house from scratch and you want rainwater capture as part of the deal, this worth considering. Concrete tanks can be poured or build from precast parts.
Raised swimming pools
In some places it is popular to use temporary swimming pools – the type with a frame on which a plastic lining is hung – to capture and store water. This is a very cheap and simple way to store water, but it has several drawbacks. The pool’s large surface makes it tricky to keep the water clean, while the lining can be easily puncture, so your entire supply could be drained in minutes. Plastics used for such pools are often also not ‘food grade’, which means they could have chemicals that seep into the stored water.