Rainwater harvesting pump systems

The pump is an essential part of a rainwater harvesting system.

A reliable and high quality pump specific for your needs is a must so that your rainwater system keeps working for years to come without a glitch. First, determine what the budget is and what is the most convenient pump for your household.

 

Other key elements which will influence the selection of the right pump are the flowrate and the water pressure needed for your household.  Basically, how you are going to use the water effectively. It is recommended to have a 250-300 kPa flow rate which  will allow you to run 2-3 devices at the same time for eg kitchen sink, laundry and shower/toilet flush or laundry and reticulation system.

 

Water pressure is also an important aspect as without pressure some appliances will not work for example your washing machine. Choose the smallest pump size (measured in Power Absorbed) for the required household flow rate. This will minimise the use of electricity hence reducing the energy bill.

There are 2 ways  to install pumps: inside or outside the water tank. Both internal and external pump systems have their pros and cons.

rainwater pump system

Internal pumps:

  • Produce less noise,
  • No need for pump weather protection or cover,
  • Safe for young kids and animals – no trip hazard,
  • Less space required for install,
  • Harder to reach inside the tank for pump maintenance,
  • Can be costly.

External pumps:

  • Need protection from the weather
  • All the connections/cabling can become trip hazards for kids and pets,
  • Noise level can be a nuisance so keep the pump system away from bedrooms or get a proper cover to reduce noise,
  • Take up more space,
  • Need a good suction line to allow for expansion and contraction of the tank,
  • Easier to maintain and monitor,
  • Fault finding is quicker to spot.

Assuming the pump has been correctly installed, the benefits for both are:

  • Good water pressure to perform household tasks like watering the garden and laundry at the same time.
  • Reduce cost of water, save money, conserve water.
  • Self sufficiency – not relying on mains water supply.

Internal pumps:

 

  • Produce less noise,
  • No need for pump weather protection or cover,
  • Safe for young kids and animals – no trip hazard,
  • Less space required for install,
  • Harder to reach inside the tank for pump maintenance,
  • Can be costly.
  • External pumps:
  • Need protection from the weather ,
  • All the connections/cabling can become trip hazards for kids and pets,
  • Noise level can be a nuisance so keep the pump system away from bedrooms or get a proper cover to reduce noise,
  • Take up more space,
  • Need a good suction line to allow for expansion and contraction of the tank,
  • Easier to maintain and monitor,
  • Fault finding is quicker to spot.

 

Assuming the pump has been correctly installed, the benefits for both are:

 

  • Good water pressure to perform household tasks like watering the garden and laundry at the same time.
  • Reduce cost of water, save money, conserve water.
  • Self sufficiency – not relying on mains water supply.

Rainwater Pump Systems FAQs 

A rainwater pump system moves water from your rainwater tank to where it is needed around the property. Depending on the setup, the pump may supply garden taps, reticulation systems, toilets, laundry, showers or other household fixtures. Without the right pump, stored rainwater may not have enough pressure or flow to be used effectively.

The pump is one of the most important parts of a rainwater harvesting system because it controls how reliably the stored water can be used. A good pump helps provide suitable pressure and flow for the intended use, whether that is watering the garden, running a laundry, flushing toilets or supplying a reticulation system.

The right pump depends on how you plan to use the rainwater, the pressure required, the flow rate needed, the size and position of the tank, the number of outlets, and whether the system is supplying irrigation, household fixtures or both. Beyond Reticulation’s page also notes that budget, household convenience, flow rate and water pressure are key factors when selecting a pump.

The required pressure depends on what the rainwater system needs to supply. The page notes that a flow rate around 250–300 kPa can allow two to three devices to run at the same time, such as a kitchen sink, laundry, shower, toilet flush or reticulation system.

Yes. Depending on the system design, a rainwater pump can supply household fixtures such as toilets, laundry, showers, outdoor taps or other approved uses. The pump must be selected to provide enough pressure and flow for the intended fixtures, and the plumbing setup must be suitable for the property.

An internal pump is installed inside the water tank, while an external pump is installed outside the tank. Internal pumps are often quieter, take up less external space and do not need a separate weather cover. External pumps are easier to access, maintain and monitor, but they usually need weather protection and may create more noise.

Yes. If the pump is too small, poorly matched or incorrectly installed, the system may have weak pressure, poor flow, unreliable performance or difficulty running multiple outlets. If the pump is too large, it may use more electricity than necessary. Choosing the smallest pump size that still meets the required household flow rate can help reduce energy use.

Rainwater pump maintenance may include checking for unusual noise, leaks, pressure changes, pump cycling, weather exposure, filters, suction lines, electrical issues and general wear. External pumps are usually easier to inspect, while internal pumps may need more planning to access. Regular checks help keep the rainwater harvesting system reliable.

Choose the Right Pump for Your Rainwater System

Get expert advice on the right rainwater pump system for your Perth property