Answers to Frequently Asked Questions
1. What is rainwater harvesting?
Rainwater harvesting is the collection and storage of rainwater for various uses like landscape irrigation, domestic use, and environment conservation. It can be used for potable and non-potable indoor purposes, and storm water/flood reduction.
2. Why is there so much interest of late in rainwater harvesting?
Rainwater harvesting is now an appreciated practice and is becoming popular because its quality is un beatable and does not require complex treatment. Rainwater is valued for its cleanliness and softness. It is slightly acidic, and is free from disinfectant by-products, salts, minerals, and other natural and man-made contaminants. With rainwater harvesting, pressure on the conventional water sources is reduced, there by conserving the environment.
3. What service does URWA provide to individuals or communities interested in learning about rainwater harvesting or implementing a rainwater harvesting program?
URWA has published a technical guide on rainwater harvesting and the 3R approach. There is a bi annual bulletin produced for information and knowledge sharing. Technical assistance to communities and individuals interested in rainwater harvesting is also usually done through capacity building in construction of water harvesting infrastructure and trainings in different aspects like operation and maintenance and WASH related topics. URWA also holds educational workshops, seminars, and conferences for stakeholders.
4. Does URWA provide funds to communities and individuals interested in installing a rainwater harvesting system?
URWA promotes different models for financing rainwater harvesting activities. These include the group for water model where by community group members contribute to the installation of a water harvesting system and URWA contributes a certain percentage (technical and financial assistance). There is also an ongoing programme of rainwater for sale whereby entrepreneurs are availed with loans to construct rainwater facilities and pay back over a given period of time.
5. I have a home with a 2,000-square-foot roof .How much water can I expect to collect at each location in a year?
In theory, a rainwater harvesting system can collect approximately 0.62 gallons of water per square foot of roof area, per inch of rainfall. In practice, however, there is always some loss due to first flush, evaporation, splash-out, overshoot from gutters, and possible leaks. Most installers use an efficiency of about 75 to 85 percent for the system.
For your home, using a collection rate of 0.62, a system efficiency of 0.85, and an average annual rainfall of 32 inches, you can expect to collect about 34,000 gallons of rainwater per year (0.62 x 0.85 x 2,000 x 32 = 33,700 gallons per year).
6. How much does a rainwater harvesting system for a typical single-family home cost?
The single largest cost in a rainwater harvesting system is the storage tank. As expected, the cost of a tank depends on its size and construction material. Other components such as gutters, downspouts, roof washers, pumps, and pressure tanks will add to the cost of the system. Professionally installed systems can further increase costs. If the intended use of the system is to collect water for drinking, costs for disinfection must be added to the total cost. Reference can be made to
7. Are there any tax incentives for installing a rainwater harvesting system?
Presently, there is an exemption from property tax for property on which a water conservation initiative has been implemented. However, individuals planning to install tanks (especially the rainwater for sale projects) should check with their respective sub county appraisal districts for guidance on sub county property taxes.
8. Are all rainwater collection systems above-ground?
While majority of the rainwater collection systems installed in Uganda are above ground, there are systems available that can be installed below ground surface. In-ground storage tanks tend to be more expensive than above-ground tanks because of excavation costs and the need to have a more heavily reinforced tank.
9. Where can I get information on manufacturers of rainwater harvesting systems?
Web sites have useful information on manufacturer's and service providers of rainwater harvesting systems. Products and services directories are also available.
10. I have a flat roof. Would a rainwater harvesting system be a viable option for me?
Yes. If the roof has a gutter that can channel the rainwater, the roof can be used.
11. Why should I be interested in rainwater harvesting when there is so much water already available for my use?
It is a misconception that there is an over-abundance of water available for our use in Uganda. The population growth increases every year and existing surface water and groundwater resources are being depleted. Already, there are places in Uganda that are experiencing shortages because demands are greater than available supplies. Rainwater harvesting provides us an opportunity to conserve and extend our existing resources.
Also, rainwater has some intrinsic qualities that should make it attractive to the user. It is pure, soft, and only slightly acidic. It is also free of disinfectant by-products, salts, minerals, and other natural and man-made chemicals that are typically added to water from centralized water supply systems. Plants tend to thrive under rainwater irrigation, appliances last longer because the water is salt-free, and the water tastes good because it is relatively free of chemicals.
12. Where can I see an installed rainwater harvesting system in Austin?
There are several household and institutional rainwater harvesting systems in Uganda that are available for public viewing. URWA operates and has members who promote rainwater harvesting in every region of Uganda.
13. Is collected rainwater safe to drink? Does it have to be inspected or tested before being used?
Collected rainwater is generally safe to drink after treatment. As rain falls through the atmosphere and on to the catchment surface it may pick up microbial and chemical contaminants and particulate matter. These contaminants must be removed before the water is used.
14. What are some of the benefits of rainwater harvesting?
There are a number of benefits to using water from rainwater harvesting systems:
- The water is God given. It is practically free: the only cost is incurred on storage devices and treatment if need be.
- The end use is located close to the source thereby eliminating the need for costly distribution systems.
- Rainwater provides a source of water when a more traditional source such as groundwater is unavailable or the quality unacceptable.
- Since it is soft water, there is no effect on the storage devices and so extends their life.
- Rainwater is free of sodium.
- Rainwater improves livelihoods (domestic use & production purposes - plants and animals thrive on rainwater too).
- Rainwater harvesting reduces the threat of flooding.
- Rainwater harvesting helps households access to water easily.
- By harvesting rainwater, households can reduce their utility bills.
15. What are some of the challenges?
Some of the challenges of rainwater harvesting are:
- Rainwater is seasonal. Because of climate change, rainfall events are highly unpredictable. Therefore, rainwater harvesting cannot be relied on as a long-term, drought-proof source of water supply.
- The cost of a rainwater harvesting system is higher than the cost of obtaining water from other conventional. However, it is paid once and for all.
- Rainwater harvesting systems require care and maintenance after installation. As a result, poor care and maintenance may result in non-functionality /loss of the system
- Rainwater storage tanks may take up valuable space around the house.
16. When and where was the first rainwater harvesting system built?
Archeological evidence suggests that rainwater was being collected for use as early as 4500 BC in parts of India and the Middle East. In China, rainwater harvesting was being practiced almost 6000 years ago. In Texas, Mescalero Apaches used natural rainwater catchment systems near El Paso nearly 10,000 years ago to collect rainwater (The Brethren of Cisterns by Robert Bryce).
17. What other countries are actively pursuing rainwater harvesting?
Rainwater harvesting is being actively pursued on almost every continent of the world. It is most prevalent in countries of Asia, Africa, and Latin America where dependence on seasonal rain necessitates that water be collected and stored where and when it becomes available. Even countries in Europe and America such as Germany and the United States have started harvesting rainwater as available traditional supplies dwindle or become contaminated.
18. Whom can I contact at URWA for more information on rainwater harvesting?
Or 1. Kikundwa Anne Birungi + 256 782 681 587/ + 256 700 308 028
- Akuku Betty Nambisa + 256 788 573 742/ + 256 700 629 270
- Ssebuliba Ronald