Three Infrastructure Considerations Before You Install A Rainwater Collection System At Home
Rainwater collection can be an excellent way to supplement your residential potable water supply by providing a source of water for flushing toilets, washing clothes and even consumption, in some areas. However, efficient, safe rainwater collection requires that collection, routing and distribution efforts be planned ahead of time. Below are a few physical infrastructure considerations you should keep in mind if you are interested in using a rainwater collection system:
Your roof serves as the collection field for rainwater, and the choice of roofing materials used will make a difference in both the quality and quantity of water collected. Below are several roofing materials and the advantages and disadvantages offered by each:
- Asphalt shingles – the most common roofing material, asphalt shingles are inexpensive and are safe to use with water that is collected for flushing toilets and washing clothes. However, asphalt shingles are porous and can absorb a considerable amount of rainwater. In addition, the presence of tar and other petroleum products inside the shingles may make their use with drinking water questionable.
- Clay tiles – clay tiles are more expensive than many other types of roofing materials, and they are also absorbent. However, the natural composition of the tiles may mean that water output is less affected by potential chemical leaching.
- Wooden shingles – as with clay tiles, wooden shingles can be costly and are prone to suck up rainwater before it has a chance to run off the roof. In addition, wooden shingles may be treated with pesticides and anti-rot chemicals which makes their use less satisfactory. Natural, untreated shingles do not have this problem, but their lifespan may be cut short considerably as a result.
- Metal roof – more expensive than asphalt but less expensive than some other types of roofs, such as clay tiles, metal roofs are in many ways an ideal surface for rainwater collection. They are durable, non-absorbent and facilitate simple draining. In addition, metal roofs can be coated with non-toxic hard finishes that will both protect the roof and preserve the quality of the water.
Eavestroughs and downspouts
Once the water leaves the roof, the eavestroughs and downspouts collect it and route it to storage tanks. Their role is important because a faulty system of transport can cause loss of water and introduce contamination into the system. Below are a few considerations that are important when designing or installing a system of eavestroughs and downspouts for the purpose of collecting rainwater:
- Protection from water loss – eavestroughs are typically designed to prevent water from flowing off rooftops onto the ground directly, but they are not usually equipped to handle substantial rainfall. For a rainwater collection system, you want eavestroughs to be deep enough to capture and convey water without loss.
- Protection from contamination – in some circumstances, trees and other external objects can fill eavestroughs with leaves, nuts, and other debris. These things are all capable of causing contamination of collected water. For example, leaves and nuts contain tannins which can leach into water and create staining and make water less palatable for consumption. That means you should consider protecting eavestroughs by installing guards or other measures that keep debris from entering them.
- Proper routing of water flow – once water is inside the eavestroughs, you want it to flow into designated locations with as little loss as possible. That requires deliberately-planned inclines that route the water flow where you want it to go. For example, you want to avoid wasteful downspouts that release water onto the ground. That may mean installing an additional network of pipe from the downspout to get the water into a storage tank.
Storage tanks hold rainwater for future use, and their importance is difficult to overstate. An undersized tank or one that is constructed of the wrong material for its particular application can be frustrating and defeat your system's integrity. Below are a few common storage tank options and when their use may be appropriate or not:
- Plastic tanks – plastic tanks are affordable, easy-to-move and can be buried or kept above ground. They are chemically-inert, so you can also store water without fear of contamination. However, they can crack during periods of freezing weather, and their appearance may be less-than-desirable, depending on one's aesthetic perspective.
- Concrete tanks – concrete tanks are usually installed on-site in an underground location. They are reasonably priced, and they also offer a unique advantage in that they can be integrated into a building's foundation. However, concrete can crack and leak if the surrounding soils shift, so keep this in mind if your locale has inadequate soil support.
- Metal tanks – these tanks are considered by many to be more attractive than plastic, and an empty tank can be disassembled and moved without too much trouble. They are strong and resist destructive forces such as freezing water. Metal tanks are prone to corrode, however, so they either need to be galvanized or constructed from stainless steel. In addition, metal tanks cannot be buried.