For LEED certified buildings, drainage system will be one pipe system or tow pipe system ? and why?

LEED doesnt have to do any thing for pipe or two pipe systems. Main purpose is to reduce energy consumption and make the overall system more efficient.

Sewage stream (also called a stream of sewage) is a separate dedicated underground transport system for the transfer of sewage from homes and commercial buildings for treatment or disposal. And take other wastewater streams that serve the industrial areas also industrial wastewater. The so-called sewage system sewer system (sewage).

Sewage works separately and independently by heavy rainfall banks, which carry special ongoing waterfalls to rain and other water which flooded the streets of the city. [Called the sewers that carry both sewage and water heavy rains together sewage collected.

Dear Sharif,

Thank you for your question. LEED does not address directly the Piping system being used. May be you can select more sustainable pipes than others like selecting pipes with recycled content or pipes having low impact on potable water or pipes which maximize energy efficiency. LEED focuses on water efficiency i.e. to reduce water in fixtures like faucets and showers etc and also to minimize amount of water used in flushes and decrease wastewater conveyed to municipal system.

Another aspect of LEED found in the latest version v4 in BD+C Multi family mid rise is "Efficient Hot Water Distribution System". The intent again is To reduce energy consumption and the burden on water supply and wastewater systems by increasing the efficiency of hot water distribution.

Hope it helps.

Basically there is no direct relation between LEED and choosing a design criteria for sewer pipes, but actually using a two pipe system to split Gray water and Black water is a good decision that enable the reuse of Gray water which will decrease the usage of potable water for sure, so using a two pipe system is preferred design Technic.