Rainwater Harvesting: Some Frequently Asked Questions

1. How do I make a rainwater harvesting system pay for itself (amortize its cost) and why should I not just harvest rainwater for irrigation.

Simply by collecting and using water harvested during the rain season and using this water in your whole household, the tank surges full very rapidly, but you draw water from the system every time you open a tap, flush the loo, or use the washing machine, or any other use of water. It removes the romantic notion of filling a water tank and not knowing what to do with the water, or trying to fill a water tank with harvested rainwater that is full already! We also make sure that you don’t unnecessarily install too many rainwater tanks so that these never have enough roof area and rainfall to fill. I.e. you draw them as fast as they recharge.

2. Why do you recommend collecting rainwater?

There are as many environmental reasons associated with rainwater harvesting as would befit a super PhD thesis. However one very important reason is to reduce stress on our estuaries from less extraction from rivers during the rain season if everyone should harvest rainwater from their roofs rather than using municipal water. It is also very important to provide the means to become as independent as possible from the municipalities supply, at the same time guarantying a supply in spite of possible and likely water outages in the near future.

3. What sort of roof should I use to maximize my rainwater harvesting?

The most efficient roof surface is a metal roof. This means a corrugated iron, flat iron sheet, or IBR profile. You cannot harvest rainwater with a thatched roof. Tiled roofs are not as efficient as metal for collecting rainwater. Here are the average calculations

11 mm of rainfall for metal roofs produce 1000 litres of harvested rainwater for every 100 sq. metres of roof area and

16 mm of rainfall for tiled roofs produce 1000 litres of harvested rainwater for every 100 sq. metres of roof area

Whatever your roof, we are able to determine precisely how much storage of rainwater you should need..

4. What size of water tanks do I need to store and use rainwater for my circumstances?

Our computer models determine the volume of rainwater storage you require depending on the following factors:

How many people are there in the house? The more people using water the less rainwater storage you need and vice versa.

What is the size of roof area? The greater the area from which you can harvest the greater storage capacity you can viably install.

What type of roof do you have? The more efficient the surface the more you can harvest.

Is your house a holiday house or do you live in it all year round? Holiday homes will naturally have greater benefit from greater storage.

Do you have our other systems to conserve water? You can halve you usage! Our other systems of conserving water will enable you to reduce your use of water (draw down) from 240 litres per person per day to 120 litres per person per day without changing your lifestyle. These systems include the Garden Rhapsody Grey Water System to re-use grey water for irrigation purposes, the Water Rhapsody Multi-Flush to minimize the volume of water required for flushing your toilet and the Water Rhapsody Poolside Tank to re-use swimming pool backwash water. One other product to make rainwater go further is our unique product to re-use grey water for toilet flushing viz the Water Rhapsody Second Movement. Your stored water will then go at least twice as far.

What is your rainfall pattern? How much and how often does it rain?

5. What water tanks sizes are available for the storage of rainwater?

The tank sizes for rainwater storage range from, 1,500Litres, and include 2,500Litres, and 5,000Litres. Though 10,000L water tanks units are available this size is very unwieldy. We decide for you as to the best size.

6. What do I get in order for me to harvest, store, and pump rainwater to my house?

Water Rhapsody Rain Runners are fixed to each and all of the downpipes, to initially harvest the rainwater. This water is fed into rainwater storage tanks, and we supply a very reliable system to pump this water from the rainwater tanks to the whole household.

7. Will the municipality charge me for sewerage effluent if I use rainwater?

The municipalities charge for water and sewerage in a block tariff system. The more you use, the higher the tariff. Municipalities charge for sewerage based only on the volume (number of kilolitres) of water that you consume. They calculated some time ago (though very erroneously) that seventy percent of the water that you consume through your water meter is wasted into the sewer as treatable effluent. Whether you have a rain harvesting system or not, (for water consumed), they will only be able to charge you for the amount of water that has run through the water meter, and the same goes for the sewerage charge, at whatever tariff is applicable, based on 70% of that metered water. You will not be charged for the rainwater used at your house. Do not think that you are being unfair: The municipality will still charge you for the effluent portion of you metered water at the rate of 70%, even though you may be re-using grey water for irrigation purposes. As a matter of interest, grey water (water from baths showers hand basins and your laundry) and black water (kitchen toilets and bidets) go in the same pipeline to the sewerage treatment works. If you do recycle grey water from your house to your garden for irrigation purposes, you send as little as 5% instead of 70% of your consumed and metered water from municipal source into the sewer for treatment at the sewerage treatment works.

8. Water tanks are ugly! How can I conceal a tank away from my house, but still use harvested rainwater.

Water tanks no longer need to stand at a wall of your house under the roof eaves.

Our system to harvest rainwater is unique. The unique item is the Water Rhapsody Rain Runner. This device is central to being able to harvest rainwater in a sustainable way. You are able to fill a rainwater tank or multiple rainwater tanks without the need for any pumping at all. You simply make use of gravity to make your rainwater harvesting sustainable. The Water Rhapsody Rain Runner is crucial to this end, and will deliver water to any place around you house or garden so long as the head of the Water Rhapsody Rain Runner is higher than the head of the tank, then harvested rainwater will be delivered in an underground pipe from the house to your tank in a ring main. All pipes from the Water Rhapsody Rain Runners around your house or commercial building are teed into the ring main.

The Water Rhapsody Rain Runner therefore makes complete system of harvesting rainwater simple, sustainable and safe.

Definition of the Water Rhapsody Rain Runner: The Water Rhapsody Rain Runner is a self cleaning device placed in your downpipe to send harvested rainwater in an underground pipe to water tanks without any chance of the delivery pipe blocking or clogging in any way. The Rain Runner receives the water, sieves out any debris and delivers this water via an underground pipe to your remote water tank.

9. How do I pressurize the rainwater for household use?

We provide all systems to harvest the rainwater (Water Rhapsody Rain Runners) the underground piping from the gutters to the tanks, the rainwater storage tanks, and a pump to pressurize the water for the supply to the building (Grand Opus pump). The pump starts soon after you turn on a tap, and switches off after all taps are closed. This is all automatic.

10. What is involved in the installation?

Installing our system to harvest rainwater (Water Rhapsody Rain Runner) into each downpipe.

Supply and installation of suitable size and number of rainwater tanks.

Pump to deliver the water to the house. If you have need for high peak times of water usage we can install more pumps in parallel to increase the higher volumes required.

Electrical supply point.

A ball valve to augment supply in the water tanks from municipal mains. This gives you an emergency supply at all times.

An override to revert to municipal mains should you rainwater be exhausted.

11. How much does the system cost?

Water Rhapsody have a set of costs to help you build a price for our rainwater harvesting system, the sum total of which is the Water Rhapsody Grand Opus. The price includes:

a. Water Rhapsody Rain Runner:

b. Water Tanks:

c. Pump including override

For a detailed quote please contact a Water Rhapsody dealer

12. For what purposes can I use the harvested rainwater?

Rainwater can be used for all household purposes, i.e. irrigation, refilling your pool, flushing your toilets, car washing, replacing municipal water etc. At the moment we are not recommending rainwater for potable purposes unless a water filtration system is installed. The quality of municipal water is deteriorating in any regions in South Africa; rainwater will become more prominent as a source of potable water.

13. Can I use my irrigation that I already have?

Yes, rainwater can go into your irrigation system as well as other household uses.

14. Do the tanks have to be stored underneath my gutters?

No. Our system of harvesting rainwater via the Water Rhapsody Rain Runners ensures that you can hide these rainwater tanks anywhere in your garden.

15. Do the tanks have to be stored above ground?

Yes. Underground water tanks are available, but are very expensive, and have the potential of popping out of the ground when empty.

16. Can I add the rainwater to the Water Rhapsody grey water system?

Yes under certain circumstances but under strict controls. The problem is the overflow. Excess rainwater should flow to a river, and excess grey water should overflow to the sewerage treatment works. You may not send grey water to a river, and our sewerage treatment works are so overloaded on the whole, that introducing extra water in the form of rainwater into the sewers is preposterous. Stored rainwater may be trickle fed into a Garden Rhapsody Grey Water Re-using System, and this saves having to purchase an extra pump to lift the rainwater to a spraying head. Let the Garden Rhapsody do this work for you.

17. How long does the system take to install?

It takes 2-3 days for us to install our rain harvesting system, including the Rain Runners, rain storage tanks, and Grand Opus pump to pressurize this water to your house.

18. Can rainwater be used instead of and/or in conjunction with Council water?

Yes, we now have several houses that live off the grid, providing total autonomy and independence. However we assure you of two things in this regard. First is to maximize the rainwater storage, and secondly our unique system provides for an emergency municipal supply in the same rainwater tanks, should you run out of rainwater. This system of the emergency supply works automatically to give you this emergency supply at all times in spite of the authorities using water outages as a means of demand management.

19. How do I switch between my rainwater tank and municipal mains water?

We supply and install a ball valve to introduce water into the water tanks for an emergency supply at all times. This water may be used freely and copiously. If you anticipate that you will not have rain for a long period of time, or you experience a power failure, we provide you with an override to revert to municipal water. This consists of a very user friendly override manifold and you switch off one valve from the pump and switch on the valve from the municipal source. We cater for every possible eventuality.

20. What about water outages: How can I use the system of rainwater harvesting to save me from being affected by water outages when the municipality turn off water in search of ways to reduce demand?

We provide you with a ball valve inserted in a low position into one tank from the municipal source of water. This will provide you with one days use of water, enough to see you through a period of outage. When the rainwater runs out, the municipal water takes over automatically, providing emergency supply.

Rainwater harvesting is one way of easing the pressure off municipal water suppliers and our over-abstracted boreholes.  Other water saving systems can be included with rainwater harvesting systems to maximize your water conservation efforts.  We also supply and install greywater irrigation systems, grey water toilet flush systems , swimming pool backwash recycling systems and special water-saving toilet flush mechanisms that simply replace your existing, water-wasting flushing mechanisms.

Water and energy are linked; renewable energy should be used whenever possible.  This has prompted us to acquire the Yes Solar Mpumalanga branch.  Yes Solar is a distributor and supplier of German-made Solsquare solar water geysers (depot is in Nelspruit / Mbombela).  Solsquare solar water heaters are SABS- and Eskom-approved and are installed by qualified solar installers (required for Eskom rebates).

Contact us for a free quote on a water system, water tank (Atlas & JoJo water tanks and JoJo tank stands) or solar geyser.  All our water systems and solar energy solutions are environmentally friendly and they save you money on your water and electricity bills!