It’s one of those double barrelled questions I get at times – ‘Do I really need a pump on my water tank?’. It comes down to what you want to do with the water you’ve collected and what you expect of your rainwater harvesting system. Gravity helps us out to a degree, but without elevation, it can only do so much when our tanks are sitting at ground level. By using large diameter hoses to reduce friction loss (25mm+) and filling watering cans to hand water the garden with, we can get by without a pump if we have the time to spare and the task at hand doesn’t require much water pressure. Setting up soaker lines in nearby garden beds can eliminate the need for a pump, but the longer the run the less water that makes it to the end of the line for an even distribution.
Can You Use A Tank Stand Like The Water Authority Do?
The reason we see massive water tanks up on hills or perched high up on stands is to create enough pressure to make the water flow through the pipes to service the local area. For the water to get to the tank, it must be pumped up there, so a transfer pump is required to do this. This is cost-effective on a large scale to serve a community, but for a homeowner in the suburbs, not so much. This is why we don’t see tanks perched high in urban backyards, it’s just not justifiable in our urban environment with all the rules and regulations. I still see the odd tank stand in semi rural and rural areas, but the cost of pressure pumps is not much more than a transfer pump and eliminates a lot of work in the process. I still love the rustic look of a tank stand with a corrugated iron tank on it, but I grew up with it on a farm as kid, so I’m biased that way.
How Do You Use Rainwater In Your Home?
Reducing demand on the mains water supply by harvesting your own rainwater and feeding it in to your home is trending right now. People are becoming more aware of how precious a resource clean water really is around the world. There are two ways to feed rainwater in to your home, both of which require a pump to do so. A plumbing loop that feeds off the mains water supply is required which can be included in a new house build or retro fitted to an existing home where the original plumbing allows it. The main difference being that one way is manually operated by switching valves as required and the other is fully automated, so the pump controller does the switchover.
The main benefit of using a manual system of valves, is that you can choose to switch your house feed back to the mains supply before the tank is empty. If you’d like to keep some rainwater available to use for drinking or making tea and coffee, then you can. Simply fitting a tap inline above the mains isolation valve allows you this choice. Monitoring the level in the tank is necessary as once it’s empty, the dry run protection in the pump will shut off the pump and no water will flow in to the house until you switch the valves back over to the mains supply. Back-flow prevention is required to stop rainwater from mixing with the mains supply in the event of a valve failure.
Who doesn’t love an automated system so they can ‘set and forget’. By utilising a three-way controller on the pump that chooses rainwater first and defaults to mains water when the tank is empty, the water feed never stops (unless the mains supply gets shut off). The cost of these controllers is slightly higher than a standard pressure controller, but the automatic switchover means you don’t have to worry about monitoring the level of water in the tank. When the controller detects the tank is empty, it will automatically allow the mains supply to take over without any interruption to your water feed.
Instant Water Pressure From Your Rainwater Tank
If you don’t want to plumb the rainwater in to your home, setting up a basic pressure pump to deliver water from your tank is relatively inexpensive and gives you pressure, which gives you many more options than gravity does. Running a sprinkler, hosing off the car, watering hanging plants with ease and utilising the water uphill from the tank are all made possible with a pressure pump. There are many different sizes of pumps to do the basics right up to running irrigation systems, so matching one to your needs is all that has to be done. Pumps can be added at any time to your rainwater harvesting system, so if you want to see how you manage without one first, give it a go. When people decide to add a pump later to their tank, they always tell us they should have done it sooner.
Setting Up A Filtration Unit
While passing water through a single sediment filter can be done with gravity straight off the tank, adding finer filtration such as carbon filtering to remove impurities and bacteria from the water requires pressure to do so. Without a pressure pump, you need time for water to pass through filters such as on counter top storage containers and filtered water jugs. While some people have the time available to continually keep topping up these units, other people are time poor and enjoy the convenience of filtered water on demand.
A simple pressure pump that is rated for potable water use is adequate to push water through a carbon or ceramic filter. When the filters are first changed, you’ll need to run water through them to remove any fine particles from the inside of the filters. There are all kinds of filtration units on the market, from single, double, triple, quadruple canister right up to reverse osmosis and UV light systems. Whichever way you choose to go, the same capacity pump will have the ability to push the water through the filtration unit.
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