Mahlet Yegizerfiker
, an up-and-coming designer with Revolution Engineering in Las Vegas, needed advice about connecting utility piping to a new townhouse development with six units per block. The civil engineer said to run separate pipes to each unit, but Mahlet wanted a second opinion from our plumbing design experts on ASPE Connect.
Our experts were quick to respond with design tips and points to investigate further, and one of them even offered Mahlet a job! “Up-and-coming designers with a thirst for knowledge are good to find these days,” Michael Tibben commented.
Questions to Ask
Nadine Callaway started the discussion by recommending some questions to investigate:
- Are there separate water meters?
- Are the townhomes individually owned?
- Are they laid out six in straight row?
- If you were an owner of a townhome, how would you want your piping done?
- What does the owner say?
Design Tips
Unless one entity is paying the water and sewer bill each month, a single water and sewer connection for a townhome block is not ideal, says Stephen Lucich, CPD. Providing a separate water meter, main shutoff valve, and sewer connection for each unit allows separate billing for usage and allows each unit to be isolated in the event of a problem.
If the block as a whole is on one water meter, C. Lyn Adair says you would want to branch off to each unit and install accessible shutoff valves at each unit before serving any fixtures. She typically shows the valves in an access panel behind the refrigerator and then feeds the unit.
Running long runs of water lines under slab also is not recommended because of the difficulty of finding and fixing leaks, says Patrick Hickey, CPD.
What if Freezing Was an Issue?
Since the project is located in Las Vegas, freezing was not an issue, but if it was, the meters would not necessarily need to be located indoors, says David Lewis, FASPE. For example, in North Carolina, even in the mountains, meters are located below grade outside the building, and in Pittsburgh meter vaults are below grade and heated. However, you have to make sure you are below the frost line, he cautions.
In areas where freezing is a definite possibility, Michael Divens, CPD, recommends routing each unit’s water supply into a closet or heated storage space adjacent to the exterior wall, rising up into the space from below the slab as close to the exterior wall as possible to avoid excessive under-slab piping.
When in doubt, check with the local utility department.
Can You Help?
The following recent discussion posts need input. Click on one of the following if you can offer some expert advice.
- When running condensate and/or safety pan drains that are smaller than 2 inches below slab, does it need to slope at ¼ inch per foot if it discharges above grade or into a drywell?
- What type of piping should be used between a concrete sump pump pit and a concrete valve box?
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