Installing a Rainwater Harvesting System: Common Mistakes to Avoid

Ethan Hartwell | May 28, 2026

A rainwater collector or a water tank—too hard to install? Léa, 27, who just installed one at her home, proves otherwise and shares savvy tips.

A rainwater storage tank for collecting rainwater: first impressions

Léa lives in northern France. She recently purchased a 310-liter cylindrical rainwater tank and shares her first impressions.

« On a Saturday morning, a truck pulls up in front of my house. Delivery of my water collector! I ordered a 310 L rainwater tank. The box is pretty bulky. The collector stands nearly 1 meter tall with an 80 cm diameter. It’s not too heavy; I can move it easily by myself. I unbox it – no glue needed, so it could also serve to build my lasagna garden given its size. It doesn’t look too complicated (at least a lot less than IKEA furniture) at first glance!»

Inside the box, she found:

  • The tank
  • The lid
  • A faucet
  • A small 20 cm hose
  • A filter / collector to place on the gutter

 

The tools I’ll need:

  • A metal saw to cut the gutter (I’ll borrow it from my husband!).
  • A drill with a hole saw to make the holes for the faucet and for the gutter connector (well, I didn’t know what a hole saw was… it attaches to the end of a drill).

The weather’s nice outside, so off to work!

Step 1: Where to place your rainwater collector?

Having a rainwater collector is great, but you also need to know where to place it in your yard.

Léa quickly solved this issue: « It isn’t very aesthetically pleasing… but incredibly useful. I’ve decided to place it along a wall on the side of my house; it won’t be visible from our deck, but it remains very accessible.
The only hitch is that the short connector tube between the gutter and the rainwater tank is only 20 cm long, which means the rainwater tank must be attached directly to the gutter…
»

She easily worked around this by buying a longer tube at a hardware store, without spending too much.

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Our tip for installing the rainwater tank

Once full, your tank will be much heavier. Think about its stability by sliding pavers or slabs underneath so it won’t sink into the ground.

A trick to hide a tank that’s too visible like Léa’s

This is the perfect opportunity to grow plants along your wall, specifically climbing plants to grow along your rainwater collector!

Step 2: Install the gutter filter/collector

For Léa, « this is probably the most challenging part to do! The ideal approach is to use a metal saw to easily cut your gutter (plastic or aluminum). Quick note: this tank is made for round gutters only. You need to cut the gutter to a height lower than the collector. The collector then snaps into the opening».

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Our advice:

Make sure you research the model you’re buying and how adaptable it is to your downspouts.

Step 3: Add the hose

The third step is to add the hose.

« The hose must have a downward slope to promote the flow of water from the gutter to the tank. A slight slope is enough».

Step 4: Drill holes in the tank!

Léa continues her guide for installing a rainwater collector in a garden:

« That’s where the drill and the 26 mm hole saw come into play (2.6 cm) ».

But where should you drill the hole to fix the pipe coming from the filter collector?

« You simply place the tank in front of the pipe, give the pipe a slight downward incline, taking care not to kink it, and mark a spot on the tank with a marker. And there you go, just drill at the mark. Then attach the pipe that comes from the gutter to the tank».

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And for the faucet?

« It’s even simpler for the faucet; drill as low as possible so you can completely empty the tank when you open the faucet. It’s also convenient for draining and cleaning the rainwater tank».

« There you go, everything is in place, now we just have to wait for the rain! It took me a total of 30 minutes to install my rainwater collector

Our tip

Be sure to check that your roof isn’t too dirty and clean it if needed, because otherwise your collector is likely to get clogged very quickly.

Performance of the rainwater collector installation

« In use, its capacity suits me perfectly for watering my garden plants and giving water to my dog. The tank has hardly ever been empty since March (okay, I live in the North…).

I recommend placing a heavy object on the lid if your tank is exposed to wind; the lid doesn’t stay well and I’ve found it several times on the terrace tiles. In terms of maintenance, not much to do: clean the filter every month to remove leaves, and the tank stays clean inside».

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Ethan Hartwell

I break down everyday products to understand what they truly contain and what they imply. My goal is simple: make information clear and useful so people can make more responsible choices without complexity or unnecessary noise.