Plumbing and drainage point layout standards for hotel public restrooms and guest rooms

Plumbing and drainage point layout standards for hotel public restrooms and guest rooms

I am Daniel Wang, a water supply and drainage specialist. The layout of plumbing points in hotel public restrooms and guest rooms is the core foundation of hotel operational comfort and maintenance convenience, directly affecting guest experience, energy efficiency and later repair costs. I have seen rework caused by improperly reserved points on multiple five-star hotel projects, so I fully understand its importance. The following elaborates on the layout standards in detail based on GB 50015-2019 "Standard for Design of Building Water Supply and Drainage" and years of engineering experience.

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I. Guest Room Plumbing Point Layout Standards

1. Water Supply Points

• Washbasin: The centers of the hot and cold water angle valves are 0.55–0.60 m above the floor (countertop height is usually 0.80 m), and the left and right centers are 0.20 m from the basin center. Article 3.3.6 of GB 50015 requires a stable hot water supply temperature; thermostatic mixing valves are recommended to prevent guest scalding.
• Shower: The centers of the hot and cold water connections are 1.10–1.20 m above the floor (surface-mounted) or 0.90–1.00 m (concealed), with a left-right spacing of 0.15 m. Article 3.3.8 of GB 50015 emphasizes that showers shall be provided with backflow prevention devices to prevent water contamination.
• Toilet: The water supply angle valve is 0.20–0.25 m above the floor (side-wall installation, 0.15–0.20 m from the toilet center) to avoid removing the toilet during maintenance.
• Bathtub: The hot and cold water connections are 0.60–0.70 m above the floor, and an installation position for the bathtub faucet shall be reserved. If a whirlpool bathtub is provided, a separate power supply and drainage connection shall be reserved (drain pipe diameter ≥ DN50).
• Washing machine/dryer (luxury suites): The water supply angle valve is 0.60–0.70 m above the floor, the drain pipe diameter is DN50, and a trap shall be provided for odor control.

• Washbasin drain pipe diameter DN32, with a P-trap; the center of the drainage stack is 0.10–0.15 m from the wall.
• Shower area floor drain diameter DN50, floor slope ≥ 2% toward the floor drain, and the floor drain center ≥ 0.20 m from the wall. Article 4.5.7 of GB 50015 requires a floor drain water seal depth ≥ 50 mm.
• Toilet drain pipe diameter DN100; the rough-in distance (wall to drain outlet center) depends on the selected model, commonly 300 mm or 400 mm.
• Bathtub drain pipe diameter DN50, with an overflow outlet.
• Case: In a five-star hotel guest room, because the shower floor drain was not sloped according to the code, drainage was slow and accumulated water seeped into the wooden floor; tiles had to be demolished and redone later, increasing costs by RMB 300,000. Linear floor drains are recommended to improve drainage efficiency.

• Hot water system: Article 5.2.1 of GB 50015 requires that the hot water outlet time in hotel guest rooms be ≤ 10 seconds; a return pipe (diameter DN20–DN25) shall be provided, with a return pump for timed circulation.
• Sound insulation: Drain pipes shall use spiral silencing pipes, and stacks shall be provided with sound insulation wrap to avoid disturbing guest rest.

II. Public Restroom Plumbing Point Layout Standards

1. Water Supply Points

• Washbasin: The hot and cold water angle valves for sensor faucets are 0.50–0.55 m above the floor (under-counter installation). Article 3.3.5 of GB 50015 requires the water supply pressure in public areas to be ≥ 0.10 MPa, but not more than 0.35 MPa to prevent splashing.
• Urinal: The water supply pipe for the sensor flush valve is 0.80–0.90 m above the floor, pipe diameter DN15.
• Toilet/squat pan: Toilets follow the guest room standard; for squat pans, the water supply angle valve is 0.25 m above the floor, and a delayed self-closing flush valve shall be provided (pipe diameter DN25).
• Mop sink: The water supply angle valve is 0.60–0.70 m above the floor, with a mixing faucet.

• Washbasin drain pipe diameter DN50 (main pipe DN75 when multiple basins are connected in series), with a trap.
• Urinal drain pipe diameter DN50, floor drain diameter DN75.
• Toilet drain pipe diameter DN100; squat pan diameter DN100 (DN75 if with a trap).
• Public restroom floor drains: Article 4.5.9 of GB 50015 requires each restroom to have ≥ 2 floor drains (1 in the shower area, 1 in the dry area), diameter DN75, water seal depth 50–100 mm.
• Case: In a hotel lobby restroom, because no dry-area floor drain was provided, water could not drain after cleaning and washing, causing efflorescence on the marble floor. This was solved by adding linear floor drains.

• Pipes: Stainless steel pipes or PPR pipes (S4 series) shall be used in public areas; drainage pipes shall use flexible-joint cast iron pipes (noise reduction, corrosion resistance).
• Valves: Each floor's water supply stack shall be provided with a maintenance valve, and the restroom entrance shall be provided with a main valve for isolation during maintenance.
• Odor control: All drainage fixtures shall be provided with traps, floor drain water seal depth ≥ 50 mm, and vent pipes shall extend to the roof.

Concluding Summary

The above are reference opinions. Actual project conditions still need further comprehensive evaluation and implementation in combination with specific operating conditions, site conditions and other factors.