As far as I know, we have three water reticulation systems, one is the direct supply, the other indirect water supply and third is the combination of direct and indirect water supply.

Direct water supply means the water takes directly from the water main. Water is supplied without pump or high level water tank.

Indirect water supply means that water from the main is pumped to water tank(s) and then distributed to the dwelling units.

So, I think "下行上给" can be translated to Direct Water Supply and "上行下给" Indirect Water Supply.

不会吧，不是这样的吧。直接给水方式是指不需设水泵水箱的给水方式，其他的是指应设水箱或水泵的给水方式！
而下行上给，上行下给都需要设水箱吧，我是这么认为的，我明年才毕业，so,有什么说错的，多多原谅，当我没说！

回学校后，我去查查！

对于供暖系统、供水系统和消防系统，含义有所不同。供暖一般采用同程式，供水一般采用水泵水箱或恒压装置，消防则需要两条以上的进户管上下的主管都需要连通的。不知你们说的是哪种系统？因为这几种系统英文翻译不一样的！

水婕版主高见啊!佩服佩服

有没有鬼佬在？能明白水婕的意思吗？