Figure 8-12. - Ground storage reservoir.

Figure 8-13. - Three types of elevated storage tanks.

GROUND LEVEL STORAGE. - During early spring, ground level storage facilities should be inspected for watertightness and structural conditions and repairs made as necessary; at other intervals, the maintenance procedures set forth in the following paragraphs should be performed.

Semiannually, exterior walls should be marked where leakage or seepage occurs. Every spring, they should be inspected for seepage or leakage from cracks-breaks or cracks in the interior seal membrane. Dewater the tank and check both the interior and exterior surfaces for spalling caused by frost action, as well as settlement, cracks, and exposed reinforcing.

All loose, scaly, or crumbly concrete should be removed and the wall patched with rich cement grout after wetting and painting with portland cement slurry. Hardened grout should be painted with iron waterproofing compound or a similar preparation.

Cracks of 1/4-inch width and l-inch depth should be chipped out. The cleaned crack should be moistened and painted with a cement slurry. The crack should be filled with a rich cement grout, dry enough to stay in place in the crack, but not dry enough to allow it to slough off. When the grout has hardened, it should be painted with iron waterproofing compound, or a similar preparation.