What base does a poly rainwater tank need to sit on?
The foundation your poly rainwater tank sits on is critical for long-term performance. A poorly prepared base can cause structural fatigue and will void your warranty.
Your rainwater tank must be placed on a base that is:
- Firm, flat, and level in all directions
- Free from rocks, stones, and sharp edges
- At least 75mm to 100mm deep
- At least 600mm larger in diameter than the base of the tank
A concrete pad is the recommended base. Compacted sand or crusher dust is also acceptable. The outer edges of the base must be retained to prevent erosion from water, vermin, or other factors. Check the base annually to make sure it has not shifted or eroded.
For chemical tanks, the slab must be engineer-rated to support the full weight of the tank without flexing or cracking.