Blue Home

Every home can help protect water resources. Not only by reducing water waste at the tap, but also by retaining rainwater, promoting its infiltration into the ground, and using drinking water only when it is truly needed.

A Blue Home is a home that works like a small sponge: it uses less drinking water, collects rainwater, slows down runoff, and, where possible, safely returns water to the soil. These are gradual, often affordable improvements that can enhance household comfort, reduce water bills, support healthier gardens, and help ease pressure on groundwater resources.

Why start with your home?

At home, we often use drinking water for activities that do not require potable-quality water, such as watering the garden, cleaning outdoor surfaces, or flushing toilets. Reducing these unnecessary uses is one of the quickest and most effective ways to lower a household’s water footprint.

The goal is not to use less water, but to use it more wisely: drinking water for drinking, cooking, and personal hygiene; rainwater for non-potable uses; water-efficient devices to reduce waste; and permeable surfaces that allow rainwater to infiltrate the ground and replenish natural water resources.

Water scarcity is now a Europe-wide challenge. According to the European Environment Agency, in 2023, 28% of the European Union’s territory experienced water scarcity during at least one season. This is why household actions, when widely adopted, become part of a broader strategy for climate adaptation and the sustainable management of water resources.

The main solutions

The main household solutions for reducing your water footprint and managing rainwater more effectively include rainwater harvesting tanks, rain gardens, permeable paving, green roofs, trees, smart irrigation systems, water-saving taps and showerheads, water-efficient appliances, and dual-flush toilets.

Tap aerators, low-flow showerheads, and dual-flush toilet cisterns are simple, often inexpensive upgrades that can significantly reduce water consumption while maintaining a high level of comfort. The actual savings, however, depend on the type of device installed, the water pressure, and household usage habits.

Energy- and water-efficient washing machines and dishwashers, when used with full loads and eco programmes, help reduce both water and energy consumption. Regular maintenance is equally important: even a small leak or a poorly adjusted irrigation system can waste a considerable amount of water without being immediately noticeable.

Harvesting and using rainwater

Rainwater can be collected from rooftops and stored in above-ground tanks or underground cisterns. It can then be used for watering gardens, cleaning outdoor surfaces, supplying toilet flushing systems (where the plumbing is properly designed), and other non-potable uses.

As a general guideline, a rainwater storage tank can be sized at approximately 30–50 litres per square metre of catchment area, depending on local rainfall, the available space, the intended uses, and local regulations.

To operate effectively, a rainwater harvesting system should include gutter filters, a first-flush diverter, closed and accessible storage tanks, a safe overflow system, and regular maintenance. The first flush is the initial portion of rainfall that washes roofs and other surfaces, carrying away dust, leaves, and other debris before cleaner water enters the storage tank.

Promoting water infiltration

An impermeable courtyard quickly channels rainwater into drains and sewer systems. A permeable courtyard, on the other hand, retains part of the rainfall and allows it to infiltrate the ground naturally.

Possible solutions include permeable paving, stabilised gravel, sunken planting beds, infiltration trenches, and rain gardens. Before installing more advanced infiltration systems, such as soakaways or infiltration trenches, it is essential to assess the soil’s permeability, the depth of the groundwater table, the distance from nearby buildings, and the quality of the water.

Any rainwater collection or infiltration system should also include a safe overflow outlet to manage excess water during heavy rainfall, helping to prevent standing water, damage to buildings, and localised flooding.

Rain garden, green roofs and trees

A rain garden is a shallow, planted depression designed to collect rainwater from roofs, driveways, or courtyards. It is not a pond: it is normally dry or only slightly moist, filling temporarily during rainfall. A rain garden combines well-draining soil, carefully selected plants, runoff reduction, and natural filtration to manage stormwater sustainably.

A green roof retains part of the rainfall and releases it gradually over time. It can also improve a building’s thermal insulation while creating valuable microhabitats for insects and urban biodiversity.

Trees are natural allies in water management. They provide shade, reduce evapotranspiration, improve the local microclimate, and help keep the soil porous, allowing more water to infiltrate. These nature-based solutions integrate soil, water, and vegetation to strengthen climate resilience and enhance the quality of urban life.

What to avoid

A Blue Home is not a home where all water is infiltrated or reused without proper planning or safeguards. Rainwater should never be directly connected to the drinking water supply without appropriate backflow protection. Oils, paints, or harsh detergents should not be discharged into drains or onto the ground. Potentially contaminated water should never be allowed to infiltrate the soil, and soakaways or other infiltration systems should not be installed without proper technical assessment.

Best practices:

• Italy (Bolzano) – RIE Index: The Municipality of Bolzano uses the Building Impact Reduction Index (RIE) to assess the environmental quality of developments affecting outdoor surfaces exposed to rainfall. It is considered a good practice because it provides a measurable way to evaluate permeability, green spaces, and water management at the building scale. Click here to learn more.
• Italy – Local stormwater management guidelines: The experiences of Reggio Emilia, Padua, and Bolognashow how stormwater management can be integrated into municipal guidelines and building regulations, linking private developments, public infrastructure, and climate adaptation strategies.
• Europe – Hamburg: Green Roof Strategy: Hamburg’s Green Roof Strategy combines financial incentives, regulations, stakeholder engagement, and technical support to significantly increase the city’s green roof coverage.
• Worldwide – United States: EPA Green Infrastructure: The U.S. Environmental Protection Agency (EPA)identifies rain gardens, bioswales, green roofs, trees, and permeable pavements as key forms of green infrastructure that help retain rainwater, reduce stormwater runoff, and improve water quality.