# Is water lost in a pipe?

If I have a very long (say, 1km) pipe in my garden (under the sun) with a small slope and put water at one end, will I receive exactly the same amount of water at the other end, with the same pressure that it was put in (if there is a motor to force the water into the pipe)?

And if not, where did that water or pressure go? Is there some kind of formula to express where the water / pressure went?

• Bernouillis Principle is what you want. – JMac May 26 '17 at 16:08
• thanks, and since i'm not very scientific, in english terms, what would be the answer to the question ? – jdoesnt May 26 '17 at 16:09
• What are your thoughts on this? – Chet Miller May 26 '17 at 16:22

1. If the water is not flowing, there will be a pressure difference due to gravity: if the inlet is a distance $h$ lower than the outlet (measured vertically), then the pressure at the outlet will be $\rho g h$ lower than at the inlet. The corollary is that if you have an inlet pressure $P_0$, the greatest height you can reach with your hose is when $P_0 = \rho g h$, so $h = \frac{P_0}{g \rho}$. For water, the rule of thumb is "10 meters per bar of pressure" (or "2 feet* per psi" - ).