Node elevation - ground or pipe elevation?

It will correspond to whatever elevation you entered.

If you used Trex and a digital elevation model, it will be ground elevation.

Tom,

Yes I do understand that. I am asking in regards to what is required for a correct water demand and fire demand analysis as I am not too proficient with WaterCAD. If the Junction is a subsurface tee or valve do i put the elevation of the proposed top of pipe at the tee or the actual ground elevation there to get correct hydraulic grade and pressure demand results? And for Junction that represents the hydrant same question. the elevation of hydrant valve where fire department would connect, ground elevation, or pipe top elevation at hydrant?

Thanks!

For most problems, it really doesn't make all that much difference (maybe 1 or 2 psi). If there are customers at a node at a dramatically different elevation than the node, and you want a high level of accuracy, then you can include their service line in the model and put a node at the customer elevation. This is seldom done unless this is some very special problem.

To add to Dr. Walski's replies - whether to use pipe or ground elevation depends on where you want to measure pressure from, and you will want to be consistent. See more in this article: What does node elevation represent in WaterCAD, WaterGEMS and HAMMER?

To add to Dr. Walski's replies - whether to use pipe or ground elevation depends on where you want to measure pressure from, and you will want to be consistent. See more in this article: What does node elevation represent in WaterCAD, WaterGEMS and HAMMER?