Rainwater Harvesting Systems

What is Rainwater Harvesting?

Rainwater harvesting is the process of collecting and storing natural rainwater from roofs for later use in the home. This sustainable practice helps conserve Ireland’s precious freshwater reserves while making the most of our abundant rainfall. Instead of letting rainwater run off into drains, it is diverted, filtered, and stored for non-potable uses such as flushing toilets, watering gardens (where space allows), or even washing machines.

In Ireland’s wet climate, a typical household roof can harvest thousands of litres of rainwater each year – often enough to cover 40-50% of non-potable water needs, depending on roof size and local rainfall. Rainwater harvesting reduces reliance on treated mains water, eases pressure on public supplies (especially during dry spells or hosepipe bans), and contributes to environmental goals like reducing urban runoff and flooding risks.

Benefits of Rainwater Harvesting in Ireland

Rainwater harvesting offers practical and eco-friendly advantages, particularly for Irish homes:

• Water Conservation: Harvest rainwater to reduce demand on mains supplies, helping preserve freshwater sources in a changing climate.
• Sustainability: Soft rainwater is kinder to appliances (less limescale buildup) and supports greener living by reusing a free natural resource.
• Resilience: Provides a backup supply during water restrictions or shortages, common in summer months.
• Reduced Runoff: Helps mitigate local flooding by capturing roof water that would otherwise overwhelm drains.
• Low Running Costs: Once installed, systems like ours operate without electricity, keeping ongoing expenses minimal.
• Suitability for Urban Homes: Ideal for terraced houses or compact sites with no gardens, avoiding disruptive excavation.

Types of Rainwater Harvesting Systems

Common rainwater harvesting systems in Ireland include:

• Underground Tanks: Large buried storage for gardens or rural homes – effective but requires excavation and space.
• Above-Ground Tanks: Simpler barrels or slimline tanks for gardens, suitable for basic garden watering.
• Indoor/Gravity-Fed Systems: Compact storage inside the home (e.g., in cupboards or attics), perfect for terraced or urban properties with no outdoor space. These use gravity rather than pumps for reliable, low-maintenance operation.

At Herr Ltd, we specialise in innovative indoor rainwater harvesting systems designed specifically for terraced houses and city homes where traditional options aren’t feasible.

Our Rainwater Harvesting Solutions for Terraced and Urban Homes

Our gravity-fed systems collect rainwater from the roof, filter it, and store it indoors without needing pumps, electricity, or large external tanks. This makes them ideal for retrofits or new builds on compact sites. The only external change is a small leaf filter box (about 8” x 8” x 8”) under the gutter.

Mini Rain Water Collection System

This entry-level system can reduce mains water use for toilets by 20-30%. Rainwater is collected from the roof, passes through a leaf filter, and is stored in tanks inside cupboards or presses. It then flows by gravity to toilet cisterns. As an option, a low-energy pump can feed additional attic storage.

Approximate Cost * €1,950 + VAT + installation by your plumber.
(Price may vary depending on household requirements)

Rain Water Collection System with Additional Storage

Similar to the Mini system but with extra tanks for greater storage capacity during heavy rain, allowing more consistent supply.

Approximate Cost: €2,450 + VAT + installation by your plumber.
(Price may vary depending on household requirements)

Advanced Option: Treating Rainwater for Wider Domestic Use

For homes with larger roof areas, we can incorporate mini sand filters (no electricity needed) to treat rainwater for uses beyond toilets, such as washing machines. These filters remove most bacteria and viruses naturally.

Sand filters alone do not meet strict EU drinking water standards, so treated water remains suitable for general domestic non-potable use (not drinking). This option is custom-designed – contact us for details.

How the Herr Rainwater Harvesting System Works

Our no-electricity system catches rainwater under the gutter, directs it indoors, and stores it in tanks hidden in cupboards, presses, hot presses, or attics. Water then flows by gravity to bathrooms for toilet flushing, with an automatic mains backup valve (also no electricity required).

Checklist for Herr Rainwater System Suitability

This indoor system works best when:

• You are retrofitting a terraced house with no outdoor space for buried tanks.
• You are building or renovating on a compact urban site.
• You want a simple, reliable system with low installation and running costs.
• You can allocate high-level space in cupboards (in hallways, dressing rooms, bedrooms, etc.) for tanks, leaving lower shelves for storage.
• You prefer a pump-free, silent operation.

Why Choose Gravity-Fed Rainwater Harvesting (No Pumps or Electricity)?

Compared to pumped systems, our approach:

• Eliminates noise from pumps switching on/off.
• Avoids electricity costs and reliance.
• Minimises mechanical parts for greater reliability and fewer faults.

Frequently Asked Questions (FAQ)

• Is rainwater harvesting legal in Ireland?
  Yes – it’s fully permitted and encouraged for non-potable uses.
• Can harvested rainwater be used for drinking?
  Our standard systems are for toilets and non-potable uses. Advanced filtration can improve quality, but we do not recommend it for drinking without full treatment meeting EU standards.
• How much space do indoor tanks need?
  Tanks fit neatly on high shelves in existing cupboards – wider/deep cupboards allow more storage.
• Are there grants or incentives available?
  Check current schemes via SEAI or local authorities; sustainability-focused installations may qualify.
• What maintenance is required?
  Minimal – occasional filter cleaning and tank checks. No ongoing electricity or bulb replacements.