# Reducing swimming pool pump output from 1.5 to 1 inch

I have a swimming pool with around 60000 liters, it uses an electric 3/4 HP pump to circulate, sweep and drain the pool. The pump is located on an underground cubicle, almost at the floor level of the pool, around 1.8 meters below the water line.

The pump inlet/outlet have 1.5 inches diameter. I am going to drain the pool, and I need to move the water about 50 to 100 meters away, and lift it 1.5 to 1.8 meters max from the pump level (almost same level as water line).

I tried contacting the manufacturer but didn't receive a response. These are the only pump characteristics I could find:

Can I use 1 inch (x100 meters) tubing for the pump output instead of 1.5in? Or will this damage the pump? (I already have 1in tubing and it turned out to be quite difficult to find 1.5 in the length I need in my small town).

• Interesting mix of units of measure. Does "1.8mts" indicate "1.8 meters"? Usually, meters is abbreviated with a simple "m". Nov 12, 2021 at 15:10
• Yes sorry, mts = meters, in my country we use metric but for tubing inches is more common.
– qsjz
Nov 12, 2021 at 15:14
• Better at 1.5” because as you go smaller you increase the losses and especially over that length. Nov 12, 2021 at 15:32
• Your pump will work harder due to an increase in pressure head. You can post your question on the "engineering forum", someone there may be offering you a better assessment. However, you should provide the current setup of the pumping - how far is the discharge point, and how height is the discharge point above/below the pump. Better to show a simple diagram of the existing 1.5" pipe.
– r13
Nov 12, 2021 at 20:34

## 1 Answer

It is unlikely to damage the pump; pump problems are much more likely to be caused by restricting the inlet. You will be reducing the outlet area by more than half so it will more than double the time necessary to drain the pool compared to 1.5 " pipe.

• That is actually good news, since the current setup overflow on the street and the neighbours dont like it too much, so if it drains slower I may not need to move it so far away. I did a test with the 1in tubing and it worked well. I was just worried it may put stress on the pump.
– qsjz
Nov 14, 2021 at 18:36