Underground water storage is an appealing, low-profile solution for your rainwater harvesting system. While more costly and detailed than above-ground tank installs, there are many advantages to installing a water storage tank system underground. Keeping your water supply safe from pests, aesthetics, inclement weather, and drastic fluctuations in temperature are just a few of the advantages of underground rainwater storage tanks. This article will discuss the basic steps of installing a water storage tank for residential or light commercial applications.
Water Storage Tank Installation: Step by Step
1. Planning And Preparation for Underground Water Tank Installation
The first step in installing a water storage tank system is to decide on the basics of your project. Determining the size and location of your underground water storage tank will help you determine how deep you need to dig and how big of an excavation you will need. This will also help you determine how long of a trench you will need for your water line and where to situate your catchment, plumbing, and other facets of your rainwater harvesting system. Knowing the characteristics of the soil will also determine the backfill required for burial. Following the tank manufacturer’s installation manual is critical to ensure proper installation.
It is also important to note that underground rainwater tanks are less accessible than above-ground storage tanks, making them difficult to add capacity or fix problems that may arise. It is important to understand the pros and cons of underground tank installation before proceeding.
2. Excavation
The excavation process is the most difficult and costly process for installing a water storage tank underground. Making sure you dig to the appropriate depth and width is important for many different considerations. These are typically noted on the tank manufacturer’s installation guide. We recommend utilizing tanks that come with ground access assemblies as opposed to being buried completely underground. This allows access to the tank for maintenance and troubleshooting when necessary.
You will need adequate depth to include backfill around the tank that will prevent it from floating. You will also need to dig a trench for your water lines from the tank area to the pumps and connectors that will bring water into your home — and to the diverter that will bring water into your storage tank. Consideration of the frost line needs to be taken into account as well, and precautions should be taken to prevent pipes from freezing if the system is going to be used in winter months.
Make sure all literature regarding installing your selected water storage tank is read thoroughly and understood prior to beginning excavation.
3. Install The Rainwater Storage Tank
Now that you have your area excavated, you will need to set the tank. Make sure that you have removed any root systems and that you have a level grade. Place bedding into the hole to allow the tank to settle appropriately. The required depth and type of bedding required will depend on the size and weight of your underground water storage tank. After placing and leveling off the bedding, set your tank in the middle of the hole. Backfill the hole and compact it on all sides to prevent floating.
4. Install Connections And Accessories
Plumb and install fittings into your rainwater storage tank. Run all lines and test that your underground water cistern has no leaks or loose connectors. Hooking your system up to an air compressor can test your airtight seals and ensure no future leaks or issues. Be sure to install any storage tank accessories that you would not be able to access later.
5. Fill In The Gaps
Finish filling in the rest of your excavation, making sure to backfill and compact as necessary. You will want to make sure that your underground water storage tank is situated below the frost line if it is being installed in an area with cold winters. Clean up the area as necessary, and make sure that your landscaping is suited to your needs. Make sure to keep any heavy equipment or machinery off of the area above your rainwater storage tank. Continue filling and compacting until you have removed any gaps or spaces around your tank to prevent unwanted moving or settling.
Now you are ready to use your underground water cistern. Storage tanks kept below ground are typically low maintenance with proper installation and will last longer than above-ground systems.