Televised ducts under slab floor. Ducts are spiral wound ducts showing heavy signs of rust and deterioration. There is standing water in the plenum. Ran water in kitchen bath and laundry and could not get water to move so it appears to be ground water. Suggest installing outside sump pit and pump to try to lower the water level. Could try at first. If necessary we may have to install a leg of drain tile through foyer then into pit. After water is resolved the ducts should be spin cast mortared and then spray lined with Duct Armor duct lining material.