Winterizing My Above Ground Water Tanks

Last year we drained the tanks and just let the winter rainfall drain off our roofs through the first flush pipes. We didn't catch any rain during the winter time.

This year, I would like to catch winter rain and at lest divert it into our pond. The problem is that when we fill the tanks, the pipes at the bottom are susceptible to freezing. We do get some periodic below freezing temperatures here in western North Carolina. Breaking the pipes will mean expense and repair before the tanks can become operational in our irrigation system.

I am looking for solutions and it involves plumbing valves.

Ball Valve

Gate Valve

I have a one inch pvc pipe buried underground. There is a such thing as a three-way diverter valve. It allows one to operate the water flow with manipulation of just one T-fitting at the junction between the flow downstream verses the flow to the irrigation pump. However, the cost of these valves is either very high, or the reviews on Amazon were less than stellar for the lower cost alternatives. 

This leads me to conclude the most cost effective method will be to dig out a box around the tank drainage and irrigation pipes. I will just install a T joint and two separate valves. 

As long as the pipes flow down hill from the valve, there should not be any water backed up into the pipes and freeze danger will be minimized.

We already have a Mueller 1" PVC Union so we can take the pump inside where it will stay warm. I will add another Mueller male fitting attached to PVC. That PVC will attach to Poly tubing and drain downhill into the pond. This is much less complicated than the underground valve system. It might not be as freeze resistant, but the simplicity makes it a more elegant solution.

I already have valves on the tanks so I can control the drains by just turning the valves on. As long as the water can run down hill, there should be less danger of freezing.