A properly winterized pool with plugged lines should hold its level, apart from a little evaporation through a mesh cover on dry, windy days. If a closed pool keeps dropping, it is losing water through the structure or a fitting rather than the plumbing, because the lines are plugged.
Watch the cover. A safety cover sagging into the pool is usually the first sign. Top up the pool so the cover is not strained, and have it checked before opening season rather than after, when the wait is longer.
Still not sure it’s a leak?
Describe what your pool is doing, and we will tell you what it may be and what a visit would involve. If the water level is dropping fast, call us right away.