Closing Pools and Frost Line

[Homebrewale]

I've read the sticky on inground pool closings. When it comes to blowing out lines and using antifreeze, it seems that advice is geared towards pools where there are deep frost lines. In my area, the maps show the frost line between 5"-10" with building codes listing the depth of 12". The pipes to and from my pool enter the ground 14" above the highest water line of my pool. I close my pool by opening all the piping on my pool equipment pad. I also remove all the drain plugs on equipment. Since it is now an open system, the water in the underground pipes should be at the same level at the water level in the pool. That means at a minimum 14" underground or 2" below the codes for frost line and likely 4" below the frost lines on front line maps. Therefore, the water in the underground pipes should not freeze since the level is below frost line at all times. So my closing procedure does not entail blowing out out pipes or adding any antifreeze. That's the procedure my pool company used before I took over openings and closings.

Is my understanding correct?

 

[1Sammy]

Question is are you ok to take a chance on doing that for the sake of a few hours work and if done correctly no antifreeze needed, just your time. I know i would sleep much better with water free lines.

 

[bmoreswim]

Yes, your understanding is correct. The only concern would be if someone lowered their pool water level closer to the level of the pipes, then they would be in the frost depth near the pool wall.

Or if there is a segment of your pipe that is plumbed such that it would hold water. Say if a "U" was formed in the piping near the pad underground. It would hold water and be subject to an issue. Small chance though.

 

[Homebrewale]

Question is are you ok to take a chance on doing that for the sake of a few hours work and if done correctly no antifreeze needed, just your time. I know i would sleep much better with water free lines.

It has not been an issue for 16 years with this pool. We don't get the frozen ground like you do in Ontario. Quite a few people, including several of my pool company's employees, never shut down their pools in this area. If building codes allow for pipes at a 12" depth, then I'm not concerned too much at 14" minimum depth. More often then not, the water level in the open pipes are more than 14" below the ground surface. The 14" comes from the distance below ground level my overflow pipe is located. Water level can't go higher than that. Now that I am moving to a solid winter cover over a mesh one, I can lower my water level more without worrying about rain raising the water level.

 

[cowboycasey]

You might get away with it but if we have another bomb cyclone who knows... Also as the pool fills back up with rain water it could be above 12 inches....

you have a VS pump, does it have freeze protection in it? I would almost say do not close your pool.. The only scary thing is if the power went out during that bomb cyclone...

 

[Homebrewale]

You might get away with it but if we have another bomb cyclone who knows... Also as the pool fills back up with rain water it could be above 12 inches....

you have a VS pump, does it have freeze protection in it? I would almost say do not close your pool.. The only scary thing is if the power went out during that bomb cyclone...

The overflow pipe keeps the pool water level at all times 14" below ground level. The only time the water less than that distance is when we receive storms with rainfall of several inches in a hour or two. The overflow pipe can't remove water fast enough but as soon as the heavy rain is over, the pool quickly returns to a water level 14" below ground level.

Your concern over loss power is why I don't keep my pool open in the winter like many other pool owners here. I feel the risk is higher that we'll get an ice storm that knocks out power while temperatures are below freezing than my pipes freezing in our relatively warm ground temperatures.