PPS 15 Planning and Flood Risk (Revised)·Page 80
Raising Services and Utilities Above Floor Level
Gas, oil, and water supplies must be positioned above the floor level to prevent joint damage, leaks, contamination, and pollution during flooding.
This would also apply to gas, oil and water supplies so as to avoid pulled joints and leaks, which can lead to contamination and pollution.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 15 - Planning and Flood Risk (Revised).pdf