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External Water Pumps vs Submersible Tank Pumps

If you plan to plumb your water tank into your home, then you will likely need a water tank pump to help deliver it to your home. Your pump can be installed inside (submersible pump) or outside (external pump)of your rainwater tank. This article will explore the differences between external (surface) water pumps and submersible (in-tank) water pumps, benefits each have and reasons for selecting one of the other.

What is an External Water Pump?

External water pumps (also known as above ground pumps or surface pumps) are the most common type of rainwater tank pump. It is usually positioned next to the tank in a weather safe location. An optional tank cover can be purchased for external pumps in a colour to match your rainwater tank. A great benefit of covers are: they can protect your pump from weather; reduce the noise of your pump; and often look nicer than seeing the mechanical components of your rainwater harvesting system.

What is a Submersible Pump?

As the name suggests, a submersible pump (also known as an in-tank pump) is positioned inside your water tank. Submersible pumps are placed inside your tank and designed to pump water upwards through the top of the tank roof.

Advantages and Disadvantages

Both types of water tank pumps have pros and cons. Here are six things to consider to help you make a decision between the two:

  1. Price – a submersible pump is more expensive to buy since it needs required waterproof casing, however keep in mind buying a pump cover can also cost a hundred dollars or so.
  2. Noise levels – one of the best aspects to submersible pumps is that they are very quiet. This is because the water they are submerged within ends up absorbing the noise of the pump. External water pumps however can be very noisy, even those that claim to run very quiet.
  3. Energy Efficiency – external water pumps need to be able to suck water in, whereas submersible pumps are surrounded in water and so just need to focus on pumping. In this respect, submersible pumps may be less complex or more energy efficient.
  4. Maintenance and Accessibility – external water pumps, should they require maintenance, are more accessible, easier to examine and work on. Submersible pumps however are located inside your tank, and so some dismantling is required before accessing your pump.
  5. Water-proof Seals – obviously required for submersible pumps, can corrode over time allowing water to get into the motor. This seal also makes motor access and repairs more difficult, and must be made waterproof again after any inspection or repair.
  6. Tank Water Space – while a submersible pump won’t displace much water, it will result in perhaps around 50 litres or so less water being storable in your tank.

At the end of the day, weigh up your pump options, costs and desired features. If your primary concern is simply ensuring your water pump can simply produce the pressure necessary to get water to where it is needed, then many tank suppliers offer tank-pump packages. Clark Tanks are happy to discuss options and provide a competitive deal.