Rule 34 of 40 · Chapter V — Water, Weather, and Place
Keep receptacles above water lines
Why this rule exists
A receptacle or connection below the level water can reach is a fault waiting for the next flood, splash, or spill. Basements flood, hoses spray, snowmelt pools, and appliances leak, and outlets, cords, and connections down at that level get immersed while energized. Water in an energized receptacle is not just a tripped GFCI; it is a corroded device and a shock hazard around the wet floor. Height is free protection you design in once. Placing devices above the credible-worst-case water line keeps electricity and water from meeting at all.
In practice
Mount receptacles, panels, and connections well above known flood and splash levels, higher in basements and garages, and above the spray zone near sinks, hose bibs, and wash areas. Keep cords and power strips off floors that can get wet, and never leave a connection lying where water collects. Where equipment must sit low, protect it with a proper enclosure and GFCI, and use listed wet-location devices. In flood-prone spaces, consider raising panels and using dedicated circuits that can be isolated. Route cords so water cannot wick along them into a connection.
When it doesn't apply
Some code-set mounting heights exist for accessibility and specific rooms; work within those while still favoring the higher, drier option. Equipment that must be at grade, certain outdoor and landscape devices, relies on proper wet-location enclosures and GFCI instead of height. In genuine flood zones, elevation requirements may be mandatory; treat local flood codes as the floor, not the ceiling.