What floor does the secondary water supply start from?

Generally speaking, municipal direct water supply is used for floors below 4-6, and fully automatic secondary water supply equipment is used for the above parts. However, some people directly use pressurization equipment from the first floor, depending on the local municipal pressure. According to the relevant regulations, the water supply pressure of the water supply company can only reach the sixth floor, which is far from meeting the needs of high-rise buildings.

Where municipal water pressure cannot be delivered, it must be pressurized twice, which is called secondary water supply. There are two standards for municipal water pressure. One is that the national regulations meet the service head of 28m (six floors); The other is 14m head (three floors) as stipulated in Document No.277 of the Ministry of Construction.

Due to different topography, the most unfavorable water pressure for water supply in local waterworks can't reach 28m head, so the head should not be less than 14m. General municipal water supply is responsible for supplying water to 1-6 floors, and secondary pressurized water supply starts from the 4th or 7th floors.

Extended data:

What people usually call secondary water supply refers to the form that units or individuals store and pressurize urban public water supply or self-built facilities water supply, and then supply it to users or for their own use through pipelines. Therefore, automatic water supply equipment is the only choice for high-rise water supply. Whether the secondary water supply facilities are built, designed and constructed according to regulations is directly related to the quality, pressure and safety of secondary water supply, and is closely related to the normal and stable life of the people.

References:

Sohu-Three Problems of Secondary Water Supply