Harvesting rainwater is an
eco-friendly way to conserve water, reduce utility bills, and support a
sustainable lifestyle. A cistern, a storage tank for rainwater, is a practical
addition to any homestead.
You can build a 250-gallon above-ground cistern
using readily available materials for about $250-$350. With basic tools and a
weekend’s effort, you can create a functional system to collect and store
rainwater for gardening, cleaning, or emergency use.
Materials Needed:
-
250-gallon food-grade plastic drum or IBC tote
-
fine mesh screen, for debris filtering
-
concrete blocks, 8-12, for a stable base
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PVC pipe - 2-inch diameter, 10 feet
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PVC fittings - 2-inch ball valve, elbow joint, and bulkhead fitting
-
silicone sealant and waterproof tape
-
hacksaw, drill, measuring tape, level, and wrench
-
hose spigot and threaded adapter
- gutter diverter kit (optional, for connecting to downspouts)
Select a flat, stable location near a downspout for easy rainwater collection. Ensure the area is accessible for maintenance and can support the weight of a full cistern (about 2,000 pounds). Clear debris and level the ground. Lay 8-12 concrete blocks in a rectangular pattern to create a sturdy base, checking with a level to ensure evenness. This prevents the cistern from tipping or cracking under weight.
Clean the food-grade drum or IBC tote thoroughly with a mild soap solution to remove any residue, especially if previously used. Rinse and let it dry. Inspect for leaks or cracks. Position the cistern on the concrete block base, ensuring the outlet (usually at the bottom) is accessible for installing a spigot. If the drum lacks a pre-installed outlet, drill a 2-inch hole near the bottom for the bulkhead fitting, following the fitting’s instructions.
Insert the bulkhead fitting into the outlet hole, securing it with the provided gasket and nut. Apply silicone sealant around the fitting to ensure a watertight seal. Attach a 2-inch PVC ball valve to the bulkhead fitting, followed by a threaded adapter and hose spigot. Tighten all connections with a wrench and wrap threads with waterproof tape to prevent leaks. This setup allows controlled water release.
Cut a 2-inch hole near the top of the cistern for the inlet, where rainwater will enter. Attach a PVC elbow joint to direct water from your gutter system. Secure a fine mesh screen over the inlet to filter leaves and debris, preventing clogs and contamination. For overflow, drill another 2-inch hole just below the inlet and attach a PVC pipe to divert excess water away from the cistern’s base, ideally to a garden or drainage area. Alternatively, you can build a “first flush diverter” to pre-filter debris, ensuring that cleaner water is collected in the cistern.
If using a gutter diverter kit, install it on your downspout per the manufacturer’s instructions. Connect a 2-inch PVC pipe from the diverter to the cistern’s inlet, ensuring a slight downward slope for smooth water flow. Secure all connections with waterproof tape. Test the system for leaks by pouring water down the gutter.
Fill the cistern with a garden hose to check for leaks at the bulkhead, spigot, and inlet. Adjust fittings as needed. Regularly clean the mesh screen and inspect the cistern for algae or debris buildup. For potable use, add a filtration and purification system, as untreated rainwater may not be safe for drinking. An RV inline hose filter is a good idea to start with, if you think you might need to drink from it.
Place the cistern in a shaded area to reduce algae growth. Elevate the spigot at least 12 inches above ground for easy bucket access. In freezing areas, insulate the cistern or drain it during winter to prevent cracking. Always secure the lid to keep out pests and ensure child safety.
For a more in depth and detailed overview and project check out:
ibctanks.com/knowledge-base/topics/rainwaterharvesting
This DIY cistern empowers you to harness rainwater efficiently, saving money and groundwater. With proper care, it can serve your household for years.