WYDave - 1/9/2025 18:12

At sea level, you can lift (suck) water up only about 33 feet, assuming your pump can pull a perfect vacuum.  Most pumps cannot, and your maximum drafting elevation will probably be about 31 feet with most fire pumps, at sea level.

If you have any leaks in your suction line - even a wee tiny little air leak - you probably will not be able to pull a column of water up 25 to 30 feet out of a pond or stream.

As you go higher in elevation above sea level, the maximum elevation you can suck water up decreases.  At the elevations we were drafting this past summer, there were times that Type  VI truck pumps couldn't pull water up more than about 18 to 20 feet, and other means had to be used to pull water (eg, Float-a-pump, etc).

 

Here's some background on the issue:

https://www.nwcg.gov/course/ffm/squirt-water/35-drafting-guidelines