Let’s leave the potable water plumbing behind and circle back to the drain-waste-vent (DWV) system.

You may recall reading about the rationales and details of the 1st and 2nd floor DWV system and looking at the installation description all the way to the roof vent.

With everything installed and documented I can now compare the schematic layouts and diagrams to the real thing.

To keep us in compliance with the Chicago and State of Illinois plumbing code, all the DWV plumbing is connected to the city sewer. But we structured the plumbing for future separation of the greywater from the blackwater without the need to open any walls. At that point we would collect, filter and store the greywater for later reuse.

Greywater stack

The future greywater system begins in the basement at the drain water heat recovery (DWHR) unit, which we placed at the bottom of the greywater stack.

The horizontal leg that currently connects the DWHR to the sewer can in the future be replaced with a small greywater collection tank that holds a sump pump and has an emergency overflow connection to the sewer.

Atop of the DWHR is a double wye, which connects to the primary greywater source, the 1st and 2nd floor showers. One leg serves the 1st floor bathroom floor drain, the second leg connects to the 1st floor shower drain, while the third leg is set aside for the 2nd floor bathroom.

If we follow the greywater stack from the basement up to the 1st floor, we find the shower drain vent that ties into the floor drain vent, effectively forming the greywater vent stack.

The leg we set aside to drain the 2nd floor bathroom continues towards the ceiling where we placed a simple wye. One branch serves the 2nd floor bathroom floor drain while the other branch connects to the 2nd floor shower drain.

Once we continue to follow the greywater stack from the 1st floor up into the 2nd floor, we can identify the floor drain and shower vent that connect to the main vent stack from the 1st floor. The stack is turning up, over and around the corner towards the main sewer or blackwater stack.

Blackwater stack

The four inch diameter blackwater stack is located in the plumbing wall with two vent lines to either side.

The two inch pipe to the left vents all of the basement plumbing. The kitchen sink vent also ties into this pipe, while the kitchen drain connects to the blackwater stack.

To the right of the stack is the two inch vent for the 1st floor toilet. The bathroom lavatory vents into this two inch pipe, while the drain connects again to the blackwater stack.

Looking at the plumbing wall from the other side, we see the 2nd floor toilet connection and vent towards the ceiling.

Moving up to the 2nd floor, the kitchen and lavatory drain are identical to the 1st floor layout, with both draining into the blackwater stack.

A little up we connect the plumbing wall vents. On the right we have the kitchen sink vent and vent from the 1st floor. To the left we have lavatory vent, the vent from the 1st floor and the 2nd floor toilet vent.

Toward the top is the vent stack connection from the showers and floor drains, before the stack turns over and up through the roof.

The only item visible on the roof is the five inch vent section of the stack. 06

Even though the bathroom lavatories are connected to the blackwater stack, we have a future plan for reusing the greywater from these sinks. There are simple and small filtering and storage systems, that would fit under the lavatory. The collected water would then be used for the toilet flushing,