As preserving resources becomes a priority, one solution makes perfect sense: harvesting rainwater. Once considered a niche alternative, it is now gaining popularity thanks to its economic and environmental benefits.
Considering rising tap water prices, recurring droughts, global tensions, and contamination risks in tap water, installing a rainwater collection system is a practical choice for today’s climate and geopolitical realities.
How Does a Home Rainwater Harvesting System Work?
You get a secondary water circuit independent of the mains supply. Rain falls on the roof, passes through primary filtration, and is stored in a sealed tank. It is then ready for non-potable uses.
What Do You Need to Harvest Rainwater?
- A clean, suitable roof (slate, tile, or metal).
- A filtration system installed before water enters the tank.
- An above-ground or underground storage tank.
- A pump if the water will be used indoors.
- A secondary network to supply the garden, toilets, and washing machine.
This setup ensures the quality of the collected water and safeguards your domestic network. An automatic switching system takes over if the tank runs low.
Can Rainwater Be Drunk?
It is possible, but only if you use a suitable, high-performance system. A gravity-fed water filter uses activated carbon to remove 99.99% of contaminants, eliminating pesticides, viruses, and PFAS, producing clean, safe water suitable for drinking.
Raw rainwater is not safe to drink, even if it looks clear. It can contain bacteria, airborne pollutants, heavy metals depending on the roof type, and organic debris. With Weeplow, you can safely drink rainwater because the filter removes all contaminants.
- Bacteria (E. coli, Salmonella, etc.)
- Viruses (with specialised filters)
- Protozoa (Giardia, Cryptosporidium)
- Heavy metals (lead, arsenic, etc.)
- Chemical residues (chlorine, pesticides, herbicides)
- Microplastics
We recommend pre-filtering rainwater to remove leaves, sand, or sediment, storing it in a clean, sealed tank, and then passing it through the Weeplow filtration system.
Maintaining Your Rainwater Harvesting System
With a gravity-fed filter, the water is safe to drink, but a poorly maintained tank quickly becomes a breeding ground for bacteria and algae, producing unpleasant odours. Clean the tank annually, disinfect with suitable products, replace filter cartridges, and inspect the pre-filter and pipes.
Regular maintenance prolongs the system’s life and ensures consistent water quality. Annual costs are modest, around £25–30.
Choosing the Right Tank Based on Needs and Environment
Consider roof size, number of household members, local rainfall, and intended uses. For garden watering, a simple above-ground tank suffices. For toilets, washing machines, or even kitchen use, a larger, underground tank is needed. Two materials dominate the market:
- Concrete neutralises rainwater acidity, maintains stable temperature, preserves water quality, and can be recycled as backfill.
- Polyethylene resists cracking and weather variations, suits hard-to-reach locations, is UV-resistant, and environmentally friendly as it is recyclable.
Even in tight times, the investment pays off, especially if mains water becomes costly. Costs depend on tank type, volume, and installation complexity. An above-ground tank for garden watering starts at a few tens of pounds.
A 6,000-litre underground system for a family of four can cost up to £5,000–6,000 including installation, covering the tank, filtration devices, pipes, pump, safety accessories, and labour. Add the cost of a gravity-fed filter with a two-year lifespan; it operates without electricity, so there are no running costs.
The return on investment is medium-term. According to estimates, such a system can save around £130 per year, equivalent to 65 m³ of potable water.
Financial Assistance for Rainwater Systems
For homes over two years old, a reduced VAT rate of 10% applies to equipment and installation. Local councils or agencies may provide grants. Check regional schemes before proceeding. Some councils offer standard above-ground tanks at reduced prices.
Is It Legal to Harvest Rainwater?
In the UK, rainwater harvesting is legal but regulated. Water from roofs containing asbestos-cement or lead cannot be used indoors. Otherwise, it can be used for floor cleaning, toilet flushing, or washing machines.
Without a gravity-fed filter, rainwater cannot be safely used for showers, cooking, or dishwashers. Any discharge into public sewers requires notifying the local council and estimating volumes. Always check local regulations before installation.
Rainwater harvesting is a forward-looking, practical response to resource scarcity, reduces environmental impact, and increases household autonomy. Given current geopolitical and environmental contexts, now is a good time to invest, with grants, real benefits, and high-quality equipment available.
Bonjour ! Je suis déjà équipée d’une fontaine Weeplow Earth 8,5l, et j’apprécie beaucoup de boire enfin une eau à laquelle je fais totalement confiance. Même le chat, qui préférait l’eau de pluie (non filtrée !) à celle du robinet, sait faire la différence ! J’ai d’ailleurs offert une fontaine à mon fils, qui n’attendait que ça !… et j’en parle tout autour de moi, en transmettant aussi l’adresse de votre site. Mais ce n’est pas la peine de BOURRER MA BAL de vos mails, je ne risque pas de vous oublier et je saurai très bien vous retrouver lorsque j’aurai besoin de vos cartouches ou d’autres produits !!! Merci beaucoup pour votre présence et au revoir !