The idea of having a green and eco-sustainable home is a dream for many. This means it’s essential to invest in systems that maximize resource use. One such system is a rainwater harvesting system.
How and why to install a rainwater harvesting system
The use of rainwater is far from a new concept. The ancient Romans already used this water collection system. The typical Roman home was built around a covered patio. At the center of the patio, near the compluvium, or roof opening, was the impluvium, a square, flat-bottomed basin designed to collect rainwater. The Roman impluvium was sunk into the ground to a depth of about 100 centimeters below the floor and was usually connected to a cistern that stored excess water, ready for use in times of need.
Today, the use of rainwater can be, and is, an excellent ally for optimizing and saving on drinking water in our homes. If properly filtered, rainwater can be reused both for watering the garden and for cleaning the house.
How does the water collection system work?
Regardless of the specific type and use, their operation always follows the same basic principle. Water is collected, filtered, stored in tanks, and then recirculated through a system of pipes and sampling pumps.
Composition of the rainwater recovery system
A rainwater harvesting system simply channels roof water into a tank through one or more downspouts.
The system is composed of specific components: a storage tank, downspout filters, and a water pump.
The first components store the collected water; they can be positioned above ground or underground, but in any case, they must be able to withstand adverse weather conditions, atmospheric agents, and possible temperature changes.
The second component, the filters, clean the collected rainwater and allow it to flow through the pipes.
Finally, the pump, as the name suggests, draws water from the tank and pumps it into the dedicated system.
In addition to these components, the collection system also includes the piping system that delivers water to the relevant utilities, and the electrical control unit, which manages the level sensors, pump, and various electrical components and valves.
The size of the system must be assessed based on the needs and a series of parameters that relate not only to the home’s water needs, but also to the area’s rainfall, the collection surface, and the material the surface is made of.
Furthermore, the system’s positioning relative to the public sewer system must be taken into consideration, as any excess rainwater may be drained into the public sewer system. For greater accuracy and safety, it is advisable to have a dual system: the collection system and the traditional water mains, both for water during drought periods and for drinking water. In some cases, it is also possible to make the collected rainwater drinkable, but this would require the use of different filters and chemicals, as well as being more expensive.
Benefits of the rainwater harvesting system
A water harvesting system offers significant benefits in terms of optimizing available resources. Specifically, it allows you to:
Conserve available water. This prevents wasting drinking water;
Save on your bill. Water costs rise exponentially if drinking water is used for multiple purposes.
How to reuse rainwater for domestic use
Not all household activities require drinking water. Rainwater can be used for a variety of purposes if first purified through proper filtration.
It can be used for:
toilet flushing
washing machines
car washing, floors
garden and plant irrigation
air conditioning and heat pumps
Legislative limits for the collection and reuse of rainwater
From a legal perspective, a distinction must be made between internal and external use. There are no limits on water use outside, while internal use must not be for food consumption. If rainwater is used inside the home, a declaration must be submitted to the municipality before any use, and certain maintenance requirements for the network, tanks, filters, and other related components must be met.
In general, to avoid penalties, it is advisable to always consult with experts in the field.