Rainwater Harvesting Pump Systems Explained.
Rainwater Harvesting Pump Systems Explained
Use tank water first and retain automatic mains-water backup when the tank supply is unavailable.
A rainwater harvesting system is more than a normal tank pump. It combines rainwater pumping with automatic source control so selected fixtures can use stored rainwater while mains water remains available as backup.
Do You Need a Pump or a Full Harvesting System?
Answer three questions. The tool will point you toward a standard rainwater pump or an automatic mains-backup harvesting system.
Answer all three questions
Your recommended starting pathway will appear here.
How a Rainwater Harvesting Pump System Works
The key difference is automatic source management. Rainwater is used while available, and a correctly designed system can switch to mains backup when the tank supply is unavailable.
Rainwater Is Available
The system detects that tank water is available for the connected fixtures.
Pump Supplies the Fixtures
The rainwater pump provides the flow and pressure needed for toilets, laundry, garden or other connected uses.
Tank Water Becomes Unavailable
The controller detects the change in rainwater availability according to the system design.
Mains Backup Takes Over
The backup pathway maintains water supply to the connected fixtures where the system is designed and installed for it.
Rainwater Pump vs Rainwater Harvesting System
The deciding question is whether the installation needs automatic mains-water backup.
Standard Rainwater Pump
Moves tank water to garden taps, irrigation or household outlets. It is the simpler option where you do not need automatic mains-water changeover.
Rainwater Harvesting System
Combines a pump with automatic control so selected fixtures can prioritise rainwater while retaining mains backup when tank water is unavailable.
If the job only requires tank water to one garden tap, hose or irrigation system, a normal rainwater pump can be simpler. If toilets, laundry or other household fixtures need continuous supply when the tank runs dry, a harvesting system may be the better fit.
Surface-Mounted vs Submersible Rainwater Harvesting
Both can provide automatic harvesting. The difference is mainly where the pump sits and how the installation is serviced.
Surface-Mounted System
The pump sits outside the tank. It is easier to access for inspection and servicing, but suction conditions and pump location need to suit the installation.
Submersible System
The pump operates inside the tank. This can reduce external pump noise and removes the same external suction arrangement, but servicing requires tank access.
When a Rainwater Harvesting System Makes Sense
Toilets + Laundry
These are common rainwater-connected household uses where automatic mains backup can maintain supply when the tank is empty.
Garden + Household Fixtures
A harvesting system can support several selected rainwater uses while maintaining a backup water source where designed for it.
Replacing an Existing RainBank
Where the tank, pipework, mains connection and electrical setup remain suitable, an existing harvesting installation can be a straightforward replacement pathway.
What Needs to Be Checked Before Installation?
Tank & Pump Position
Tank access, pump location and whether the system is surface-mounted or submersible all affect installation and servicing.
Connected Fixtures
Toilets, laundry, garden taps and irrigation determine the likely simultaneous flow and pump duty.
Mains Backup Connection
The backup plumbing, valves, separation and backflow requirements must suit the installation and local requirements.
Electrical Supply
The pump and controller require suitable electrical supply. Electrical work is a separate consideration where changes are required.
Pipe Size & Condition
Existing pipework, valves and fittings affect flow, pressure and whether the replacement setup can be reused.
Existing Controller
If only the pump or controller has failed, diagnose the failed component before replacing the complete harvesting system.
Compare the Right Pump Category
Choose a harvesting system if automatic mains backup is part of the job. Choose a standard rainwater pump if you only need to move tank water.
Rainwater Harvesting FAQs
What is a rainwater harvesting pump system?
It combines a rainwater pump with automatic source control so selected fixtures can use tank water while retaining mains-water backup when rainwater is unavailable.
What is the difference between a rainwater pump and a RainBank system?
A standard rainwater pump simply moves water from the tank. A RainBank-style harvesting system adds automatic mains-water backup and source control.
Do I need mains backup for a garden pump?
Not necessarily. If the tank only supplies a garden tap, hose or irrigation system and automatic backup is not required, a standard rainwater pump can be simpler.
Can rainwater harvesting supply toilets and laundry?
Yes, where the property is correctly plumbed and the system is designed for those fixtures. Automatic mains backup is commonly used so those fixtures retain water supply when the tank is empty.
Is a submersible RainBank system better?
Not universally. Submersible systems can reduce external noise, while surface-mounted systems are easier to access for servicing. Tank access and installation layout should decide the better arrangement.
Can I replace only the pump in an existing harvesting system?
Possibly. If the controller remains serviceable and compatible, only the failed pump may need replacement. The failed component should be diagnosed before replacing the complete system.
What happens when the rainwater tank is empty?
In an automatic harvesting system, the controller can provide mains-water backup to the connected fixtures when rainwater is unavailable, subject to the specific system design and installation.
Does a rainwater harvesting pump work during a power outage?
The pump itself requires electrical power. Any water availability during a power outage depends on the correctly installed mains-backup pathway and the specific system arrangement.
Choose Automatic Harvesting Only When You Actually Need It
If the property needs rainwater priority with mains-water backup, compare a harvesting system. If you only need tank water moved to a garden or irrigation outlet, a standard rainwater pump may be the simpler choice.
