A back up valve installed in the sewer line is more NOTE: Alternate direction of sacks with bottom layer parallel to flow, next layer perpendicular to flow, etc. Lap unfilled portion under next sack. Temp thoroughly in place. Sacks should be approximately 1/2 full of sand.

A back up valve installed in the sewer line is more NOTE: Alternate direction of sacks with bottom layer parallel to flow, next layer perpendicular to flow, etc. Lap unfilled portion under next sack. Temp thoroughly in place. Sacks should be approximately 1/2 full of sand.