Underground rainwater harvesting maintenance tips

General Maintenance

Once an underground tank is installed access is limited (particularly for the tank and components that are underground). Therefore it is of utmost importance to ensure all installation guidelines and manufacturer’s specifications are followed to ensure proper functionality. A properly installed underground tank requires very little maintenance.

Here are few things that will help prolong your system’s life, reduce the potential for damages and ensure you get maximum benefit from it.

Excavation/Backfill

  1. Underground tanks should be placed on natural soil with a bearing capacity greater than 120kPa.
  2. Avoid installing the tank:
    1. In water saturated clay or an area that is frequently flooded
    2. Where depth to bedrock is less than 2.5m
    3. In the path of vehicles/heavy equipment
    4. Where underground services are expected (i.e. electric cables, water/sewer pipes and gas lines).
  3. Excavation, bedding, backfill and dressing will vary depending on the location, type of soil and the size of the tank. Follow manufacturer’s installation guidelines relevant to your setup to ensure proper functionality and to prevent damages.

Tank Maintenance

  1.  Tank Lid - Check that the lid of the tank remains in place. The tank lid should be filled with concrete (when installed) to ensure it stays in place during all weather conditions.
  2. Fittings & Connections - Generally check all fittings and pipework connections (above ground) at least every 3 months for leaks and signs of damage.

How To Maintain Your Underground Rainwater Harvesting System

  1. Rooftops - Rooftops should be cleaned regularly to avoid contamination of the runoff. During dry weather, dust, leaves, animal excrement and dead insects accumulate on the roof. Make sure that the roof is cleaned before the rainy season starts, followed by a monthly check to keep it clean.
  2. Overhanging Branches - Check that branches overhanging the roof are regularly trimmed back.
  3. Gutters - Ensure that the gutters are free from leaves - consider installing gutter mesh.
  4. Pre-Filtration - Regularly check the pre-filtration device/s to ensure that it is free from leaves and that rainwater can pass through.
  5. First Flush Diverter - If a first flush diverter is installed, check and clean it out on a monthly basis.Ensure the diverter is dripping out sufficiently to reset the system.
  6. Pump Efficiency - Check to see if the submersible pump is functioning properly and that there are no signs of damages to the pump or its power cord. To ensure proper pump operation it is important to comply with the provided recommendations and specifications (see instruction mannual).
  7. Keeping your tank Clean - Inspect the inside of the tank every 3 months to make sure that leaf litter has not built up in the bottom of the tank. A properly designed system should not allow leaves and other material to get into the tank.
  8. Water Quality – Please remember that water collected from a roof will not be clean. If the intent is to use the rainwater for drinking purposes, consult an installer with experience in installing water filtration systems. For irrigation purposes however, the water would be perfect.

How To Maintain Your Conservancy Tank

Find a licensed hauling company in your area with adequate equipment to transport and dispose of the contents when the tank is full.

How To Maintain Your Septic Tank

Ensure that only septic friendly chemicals are used to clean all the toilets feeding into the tank as a septic tank is not chemical resistant. Septic friendly chemicals can be identified by viewing the labels on the back of the products. Note: one teaspoon of dishwashing liquid can result in system failure for up to seven days.