Full-open valves shall be installed in the following locations:
- On the building water service pipe from the public water supply near the curb.
- On the water distribution supply pipe at the entrance into the structure.
- On the discharge side of every water meter.
- On the base of every water riser pipe.
- On the top of every water down-feed pipe in occupancies other than one-, two-, and three-family residential occupancies.
- On the entrance to every water supply pipe to a dwelling unit, except where supplying a single fixture equipped with individual stops.
- On the water supply pipe to a gravity or pressurized water tank.
- On the water supply pipe to every water heater.
Shutoff valves shall be installed in the following locations:
- On the fixture supply to each plumbing fixture other than in individual sleeping units that are provided with unit shutoff valves in hotels, motels, boarding houses and similar occupancies.
- On the water supply pipe to each sillcock.
- On the water supply pipe to each appliance or mechanical equipment.
Each gravity or suction water supply tank shall be provided with an overflow with a diameter not less than that shown in Table 606.5.4. The overflow outlet shall discharge at a point not less than 6 inches (152 mm) above the roof or roof drain; floor or floor drain; or over an open water-supplied fixture. The overflow outlet shall be covered with a corrosion-resistant screen of not less than 16 by 20 mesh per inch (630 by 787 mesh per m) and by 1/4-inch (6.4 mm) hardware cloth or shall terminate in a horizontal angle seat check valve. Drainage from overflow pipes shall be directed so as not to freeze on roof walks.
A valved pipe shall be provided at the lowest point of each tank to permit emptying of the tank. The tank drain pipe shall discharge as required for overflow pipes and shall not be smaller in size than specified in Table 606.5.7.
| TANK CAPACITY (gallons) | DRAIN PIPE (inches) |
| Up to 750 | 1 |
| 751 to 1,500 | 11/2 |
| 1,501 to 3,000 | 2 |
| 3,001 to 5,000 | 21/2 |
| 5,000 to 7,500 | 3 |
| Over 7,500 | 4 |
For SI: 1 inch = 25.4 mm, 1 gallon = 3.785 L.
All water pressure tanks shall be provided with a vacuum relief valve at the top of the tank that will operate up to a maximum water pressure of 200 psi (1380 kPa) and up to a maximum temperature of 200°F (93°C). The minimum size of such vacuum relief valve shall be 1/2 inch (12.7 mm).
Exception: This section shall not apply to pressurized captive air diaphragm/bladder tanks.