Are 90 degree fittings that bad?


Well-known member
Apr 28, 2017
Earlier I posted asking if I should use rigid pipe or flex. I got a resounding rigid. Another question: so the reason my pool guy quoted 450 dollars supposedly is because the pipes needed to be redone. The current pump has a 90 degree fitting right out of the top, followed by another 90, and another 90 into the filter. They all touch. The pool guy said this would cause the pump to overheat...

Many things I hear from pool people get debunked here, and this sounds fishy. I'm curious if there is any truth in this? The engineer in me says, not likely... I feel like the bottle neck is either the filter or the rise up to the solar panels, or the panels themselves. Am I wrong?

I do see a problem with the pump being so close to that first 90, as it might be bad having that much pressure on the pipe, so I am probably going to add some pipe there, but is there any benefit in adding the giant loop of sweeping pipe bends the pool guy is recommending?


LifeTime Supporter
Sep 11, 2010
Orange County, CA
I'm not an expert in this area, but I have heard that you want some straight pipe coming out of your pump. Looking at what the professionals did when they re-plumbed my pool, I see there are to 90s and a 45 coming out of the pump and into the filter. There's not that much straight lead pipe or pipe coming out of the pump; probably not more than a foot. I'll be interested to see what other people say.


Well-known member
Mar 17, 2015
Cedar Falls, Iowa
My set up is about 12 inches to the first 90 deg. out of pump to filter, and about 6 more as everything heads into heater and couple more out of heater to return.
7 years and still same pump. Pressure gauge on filter usually stays at 15lb. when clean. If I avoided close elbows, I would have a racetrack figure 8 set up.
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Gold Supporter
TFP Guide
Jun 7, 2017
Damascus, MD
In an ideal world, you'd have all straight piping and as gradual a bend as possible where needed. In the real world, it doesn't make as much difference as you think on loss of flow. There is a hydraulics article somewhere if I find it I will post it but for our practical use, the extra 90s do not add enough to worry about. Yes it is measurable but not to the extent you should do something about it.

With your system, I would have moved the pump over so the pressure side is lined up with the input to the filter and then you need just a single 90 or perhaps even a sweep elbow and you could still do that if you wanted but realistically, it isn't going to make that much of a difference.


Bronze Supporter
Jun 1, 2016
Gilbert, AZ
As poolgate says, but if you really want to make a change and not move the pump (which would be the cleanest install), I’d bet it also could also be done cleanly with 3 45-degree fittings and a bit of experimenting.


TFP Expert
Mar 2, 2011
Having multiple 90s right next to each other is not ideal but it certainly can't cause the pump to overheat.

As long as the flow rate is not excessive, the installation should be fine.
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TFP Guide
May 10, 2017
Hays, Kansas
The 3 90's are equivalent to 18 feet (guess) of pipe, so no not ideal and will cause a slight pressure increase.

The real trouble I have with that is the potential for leaks, every connection is a potential leak spot and you have a bunch there. If you are repluming now is the time to fix that


LifeTime Supporter
TFP Guide
Oct 25, 2015

Most good piping designers will want to optimize the pressure drop in the system. As James points out the pump doesn't really care what kind of pressure drop it sees. It will just perform to it's pump curve. A little more pressure drop decreases flow, it does not overheat the pump. Piping design is often a tug of war between cost and minimum pressure drop. Lowest cost is usually a very compact design. Optimal pressure drop is usually more spread out but costs more, and usually easiest to maintain.

I hope this helps.