Installing a Rain Water Pump

I have this big 1000 litres tank that I collect rain water in, but I’m too lazy to actually carry the water in a 10 litres watering can out in the garden. That’s why I have installed a water pump in the tank to do the job.

I’ve spent a long time looking for a pump that was small enough to pass through the hole in the top of the tank since it had a nice screw-cap:

Unfortunately I didn’t find a pump that would fit so off with the cap. My friend Mr. Dremel helped me out:

Notice the colour of the rain water; this tank needs to be emptied soon 😉 I even noticed a couple of insects swimming around down there. Gross.

With the plastic perforated the remaining screw thread was cut away with a stanley knife:

This brand new Alko Rain 2500 rain water pump fits in the new hole in the water tank. I paid about 500 dkr. ($100) for this one.(230 V~, 350 W, H max 11 m, Q max 2.5 m3 / h, D 3 m.) The valve is just left fully open:

Yep, it fits and stands on the bottom. I’ve attached an extra string just in case:

I’ve put a wooden lid on top of the tank to keep small animals away so they won’t fall into the tank and drown:

Yes! It works. But I would estimate that it only delivers about 80-90 % of the pressure compared to tap water:


The rain water pump is connected to 42 metres (138 feet) of 0.5 inch hose so maybe that’s a bit too much for the pump. I’ll try to shorten the hose and see what happens.

When I turned off the pump I was surprised to see that the water kept coming out of the sprinkler:


This is due to the natural flow since the tank is placed a couple of meters higher that the sprinkler. It’s solved by disconnecting the sprinkler and using a connector with built-in stop valve.

The rain water pump system is working fairly well so the next step is connecting it to the soil moisture sensor system and build the automatic watering system I keep blabbering about 😉

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