Bidet water lines must be a minimum size and type of

• A. 3/4 inch cold and hot
• B. 1/2 inch cold and hot
• C. 3/4 inch hot only
• D. 1/2 inch hot and cold

Answer: (B)

Bidet supply lines must deliver enough water flow for both temperature and spray to work comfortably. Using lines that are at least 1/2 inch in diameter for each side—hot and cold—ensures the fixture gets enough water without excessive pressure loss as it passes through shutoffs and fittings. Smaller lines can restrict flow, leading to a weak spray or uneven temperatures. A 3/4 inch line is larger than necessary for a typical residential bidet, and having only one side (hot or cold) would prevent proper mixing and safe operation. So, the required setup is 1/2 inch for both hot and cold supplies, using a potable-water-approved material (such as copper, CPVC, or PEX) with accessible shutoff valves.