Is Purple Pool Water Safe To Swim In?

white backyard pool next to porch of one story home with purple pool water inside from copper staining

If your pool is purple, you are probably shocked at the appearance.  What could cause this?  Your practical side is also wondering is purple pool water safe to swim in?  There are a couple of reasons your pool water might be purple, and one imaginary reason.  We will review them below.

Why Does My Pool Have Purple Water?

First, there’s a somewhat rare, but well known reason your pool is purple. Your CYA reading is above 100 and you have copper in the water. This creates copper cyanurate. This lavender colored water chemistry imbalance is one of the most beautiful problems you’ll ever have with the pool. This is usually a problem with salt pools which lack the zinc sacrificial anode, but it happens with traditional chlorine pools as well.

Is Purple Pool Water Safe To Swim In?

What happens is that corrosion occurs in the pool.  Whether galvanic corrosion due to the salt in the pool, or corrosion due to poorly managed chemicals in a chlorine pool. The corrosion attacks the copper heat exchanger in your heater. 

Usually the copper in the water is from the heat exchanger. However, sometimes the copper is due to the makeup water you refill the pool with from your hose. When you combine this copper in the water with too much stabilizer / CYA to the pool, you will end up with a purple pool. It’s a beautiful problem to have, but definitely do not swim in the pool.

backyard pool begging the question is purple pool water safe to swim in because there is purple water and no one is near the pool

How To Get Rid Of Purple Pool Water

First you will need to drain down the pool. Do this via a couple feet at a time. Then refill until your CYA readings are back into balance, 30-50 PPM.  Then you’ll need to use a metal remover to sequester the copper in the water. This will be followed by filtering it out to prevent any further staining to the pool.  We recommend Proteam’s Metal Magic.

Proteam Metal Magic (1 qt) (2 Pack)
  • Removes metals from pool water
  • Aids in removing fresh metal and scale
  • Compatible with all filtration systems

In really bad cases where there is a lot of copper, the sequestering process may take a few days.  Keep an eye on your filter pressure and backwash / clean the filters as necessary.

Next, there is the circumstance where it’s night time, and the pool has a color changing light.  The pool can appear purple when the color changing light is on.  So is purple pool water safe to swim in when caused by a purple light? 

In this situation, the purple pool is just as safe as a green pool or a red pool or white.  If you have trouble seeing the bottom of the pool, or the light seems too dim to see anything, ask that the light be changed to white so you can see better.

The last reason your pool might be purple is the imaginary one. For years there has been a warning out there that there’s a chemical you can put into pool water that turns the water purple if you pee in the pool.  This was invented to scare people into not peeing in the pool.  This color changing urine indicator dye is one of the most prevalent but completely false myths about swimming pools out there.  If your pool is purple, this is not why.

Is Purple Pool Water Safe To Swim In Summary

So, is purple pool water safe to swim in?  Like many answers to questions we have answered in the past, that depends.  The cause of the purple pool will determine whether it’s safe. If your pool is a copper-cyanurate chemical mix and that’s why it’s purple, do not swim

If the colored light is making the pool purple, it’s just as safe as any other pool.  And if your pool is purple because someone peed in the water?  In this circumstance you are currently living in a parallel universe where color changing urine detection chemicals exist.  If that’s the case, you may want to question everything you know. There are many pool maintenance myths, and much like cleaning your pool with vodka, this is imaginary.