You have seen the light. A liquid tank, be it to store water, remove sewage or keep grease under control, is a great investment for your property. But it’s not as easy as dropping a tank at the closest convenient spot. If you want lasting quality and performance out of your tank, and not fix costly mistakes later, the ‘where’ is very important…
You are spoilt for choice when it comes to rainwater tanks. They can be small or enormous, depending on how much water you want to capture and store.
The simplest placement is simply underneath the downpipe, which is how the water travels from the roof drains down to the ground. You can place a simple plastic container at the bottom, such as a dustbin, or connect a series of plastic drums to it. A very elegant solution is to install a small rainwater tank, such as our 260 litre models, which include a lid system to protect the water and a tap for easy access. But you can go as large as 10,000 litres.
Once you start moving a tank away from the capture areas, which will likely be your roof and gutter system, you have to consider the piping that will feed rainwater into the tanks. If the tank is elevated, it may require a pump (and thus electricity to power the pump). Likewise, consider the piping you’ll need to move water from the tank to where you need it, such as an irrigation system.
You should also keep weight in mind. A litre of water equals a kilogram, so a 10,000 litre tank will put 10 tons of weight on the ground. It is best to have a flat, reinforced surface for your tank, such as a concrete slab or brick floor, and to use a metal frame if you want to raise the tank off the ground. Avoid putting the tank too close to spots where the ground may be weak, such as the top of an embankment.
Many of the principles used for rainwater tanks can apply to greywater tanks. The difference is that the latter captures water from the building that was produced by washing machines, shower runoff and such places. Anything that involves organic material, such as dishwater and sewage, does not go into greywater storage.
Greywater is captured typically for irrigation or to replenish building water such as the cisterns of toilets. So how the water gets to its destination is a key consideration. Greywater won’t sit as long as rainwater, so you won’t need massive tanks. This allows you to put greywater tanks close to buildings – just remember that you will need a pump and filter system (which will need power).
A greywater system can ideally be connected to your building’s plumbing. But be sure to use a qualified professional for this.
Septic and Conservation Tanks
Both septic and conservation tanks are typically buried. This is for two reasons: first, they take up a lot of space, and second, they shouldn’t be exposed to the outside world. It also makes sense, since your sewage plumbing will run underground.
Because of this, you have to be certain where the tank will go. It needs to be in easy reach of the building’s plumbing, yet isolated enough not to become a safety hazard. If the tank needs to be drained periodically, a suitable truck must be able to reach it. That being said, the tank should be in a spot where vehicles and other heavy objects can’t stand on top of it – for obvious reasons!
Depending on the sewage system, you may also have a drain field. This is where treated liquids are funnels, where they are absorbed by the ground. Again you don’t want vehicles to traverse that field, as it is likely to be marshy and soft.
Since septic tanks pose a health hazard, there are regulations around their placement. Do not install a septic or conservancy tank without the input of a qualified professional.
Grease and oil do not mix with water. The result is the slow build-up of grease residue in pipes, which begin to snag other objects and consequently create blockages. In establishments that process a lot of grease and oils, such as auto workshops and kitchens, capturing these waste materials can more crucial and sometimes even a legal requirement.
A grease trap comes in different designs, but the principles are the same: you want to be as close to the source as you can. In some cases, grease traps are inside the work area, standing between the basin and the rest of the outgoing plumbing. The ideal location is a question of the design of the work area and the amount of grease that you expect to capture.
The second consideration is the ease of maintenance. Grease traps need to be cleaned out, so you want a spot that is easy to access, but won’t stop work. This is one reason why some places do not allow grease traps indoors, as they can be a health hazard.