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The Secret Ingredient for a Thriving Pond

22nd Apr 2024

We're frequently asked by our customers 'what's the best way to fill up my pond?' The answer is - rainwater! We know that harvesting enough rainwater to fill your pond isn't quite as simple as it sounds, so when writer Hannah Walters got in touch and asked if we could publish her article on our blog, it was a very easy 'yes!'

Below Hannah talks about the benefits of using rainwater to fill your pond and the best way to do it. If you're thinking of creating a pond, we'd highly recommend reading the below and following Hannah's tips for harvesting rainwater. 

The Secret Ingredient for a Thriving Pond: Harvested Rainwater

Ponds look beautiful in backyards, and they’re even better full of life and plants. Residents aiming to be more eco-conscious are starting to opt to use rainwater to fill their ponds. This isn’t just a trend though; it helps the planet and makes the pond’s ecosystem healthier.

Why harvested rainwater?

Harvested rainwater doesn’t contain chemicals like fluoride and chlorine, which tap water does. Rainwater is completely natural and is much better for fish and plants. Not just that, it’s pure and has natural nitrates, ammonium, and organic matter, helping plants and wildlife to grow. When good bacteria start to grow in your pond, it helps it take care of itself.

Note: rainwater will still need to be filtered to protect the pond from pollutants and dust.

Setting up a rainwater harvesting system

Size up your tank – This will depend on factors like catchment area, average rainfall, and water usage. Calculating this beforehand will make sure you’ve got enough water for your pond and garden, allowing for proper overflow to avoid flooding.

Keep it clean – For your rainwater system to be successful, it must be clean. You can use a first-flush diverter and a downspout to help stop things like leaves, dirt and bird droppings getting into the tank.

Multiple system options – There’s plenty of options available. You can opt for systems that work by gravity, pumps, or filters. It all really depends on the space in your garden and the size of your pond.

Rainwater and your pond ecosystem

Harvested rainwater is just as good for fish as it is for plants. The lack of chemicals helps fish to stay vibrant. It’ll also keep your water nice and healthy by mixing in extra nutrients, keeping the PH levels balanced and helping good bacteria to grow. You’ll have a nice stable pond that’s protected from harmful algae and other problems.

Other benefits of harvested rainwater in your garden

Not only will your pond benefit but you can use harvested rainwater on the rest of your garden too. Distribute it to the plants throughout your backyard to prevent waste. You can even buy attachments to incorporate water features into your garden landscape that fit your tank or hose.

You’re reducing your reliance on treated tap water, by finding a use for rainwater that’s already falling on your property.

The cost of installing a rainwater harvesting system

The set-up costs are quite high, but you’ll notice it pays for itself by saving you money on water bills. There’s an option to go completely independent from your water supply, but this will require plenty of work and equipment to make sure everything’s filtered properly.


A thriving pond will bring plants, animals, and rainwater together to create a complete ecosystem in your garden. Using harvested rainwater to fill your pond is more than simply saving water, it’s also about choosing a greener, more eco-friendly garden. The lack of chemicals compared to tap water offers a more nutrient rich source for wildlife. Just make sure it’s still filtered to remove pollutants and dust from the atmosphere. There’s no need to worry about space as there’s plenty of options for gardens of all sizes.  

Written by Hannah Walters