Twenty Years On: Why Filtering Your Rainwater Before Storage Still Matters

Sometimes the best recommendation for a product isn't a brochure or a specification sheet; it's the fact that someone is still happily using it nearly 20 years later.

Back in 2007, the West Wales Eco Centre in Newport Pembrokeshire, just down the road from us, installed a range of sustainable technologies to demonstrate practical environmental solutions. Among them was a 3P Filter Collector, connected to a rainwater harvesting system that included a large storage tank and pump supplying non-potable water around the building.

When the Eco Centre eventually sadly closed, much of the demonstration equipment was removed. One component, however, remained quietly attached to the building's downpipe: the 3P Filter Collector.

A Second Life at Real Seeds

Today, that same building is home to Real Seeds, an independent seed company dedicated to helping gardeners grow open-pollinated vegetables and save their own seed. Rather than leaving the filter unused, Real Seeds founder Ben Gabel recognised it still had plenty of life left.

He removed the filter collector and gave it a new purpose at home, where he grows and trials new vegetable varieties on a large garden plot under real backyard conditions before they are introduced into wider seed production. You can read more about Real Seeds and their approach to seed growing on the Real Seeds website.

The filter now collects rainwater from the roof of Ben's barn. It feeds it into a 2,000-litre storage tank, providing a valuable supply of water for manual irrigation throughout the growing season.

With recent summers bringing longer dry spells and more frequent heatwaves, harvested rainwater has become an increasingly important resource for keeping plants healthy while reducing reliance on treated mains water.

One Small Repair After Nearly Two Decades

Remarkably, after almost 20 years of service, the 3P filter collector required just one simple repair.

The only component that had deteriorated was the internal rubber sealing washer. Once this inexpensive part was replaced, the unit was back to working exactly as intended, efficiently diverting clean rainwater into the storage tank again.

That's an impressive testament to the quality of the original design and materials.

Why Filter Rainwater Before It Enters the Tank?

Many people install a basic rainwater diverter and assume that's all they need. However, filtering rainwater before it enters storage is one of the most important steps in any rainwater harvesting system, whether you're filling a small water butt or a much larger storage tank.

Roofs naturally collect leaves, moss, twigs, feathers, insects and other debris. Without proper filtration, all of this material can end up inside your water butt or tank, where it gradually breaks down into sludge and can begin to smell.

Using a dedicated filter collector offers several important advantages:

• It removes leaves and larger debris before they reach the storage tank.
• Debris continues harmlessly down the downpipe instead of clogging the system.
• Cleaner water helps reduce sludge and algae build-up inside the tank.
• Pumps, hoses and irrigation equipment are better protected from blockages.
• The collected water stays fresher for longer, making it ideal for watering plants.

3 in 1 Filter Collector

The 3P Filter Collector is not just a downpipe filter; it is also a diverter/connector and (when installed correctly) acts as an overflow too!

It uses a durable stainless steel mesh to filter out particles larger than approximately 0.7 mm while allowing rainwater to flow efficiently into storage. When the tank is full, it automatically functions as an overflow, allowing excess water to continue safely down the downpipe. It also features an "Open/Close" setting, allowing collection to be switched off if required.

Ideal for roofs up to 90m².

Built to Last

Sustainable products should do more than reduce environmental impact; they should also stand the test of time.

Ben's experience demonstrates exactly that. Installed as part of an Eco Centre demonstration nearly two decades ago, the same filter collector is still providing clean harvested rainwater today, with only a replacement rubber seal needed along the way.

Hopefully, as Ben puts it, "it'll be good for another 20 years."

For gardeners, growers and anyone looking to make better use of the rain that falls on their roof, it's a reminder that investing in a quality rainwater filter isn't just about collecting water; it's about protecting that water before it ever reaches the tank.

If you'd like to learn more about the 3P Filter Collector and other rainwater harvesting solutions, contact our friendly team.

We totally recommend Real Seeds for gardeners looking to grow unusual and non-hybrid vegetables.