[JRTJH]

Unless there are valves at the T's where the laundry connection splits away from the hot/cold water lines, then when you pressurize your water system, you'll push water into that plumbing. So, there's probably water in the lines. If (with Keystone who really knows) there is a sag in the line, it may not drain through the low point drains. That could lead to damage from a hard freeze.

So, even if you have never used the lines, chances are better than good that you have water in that plumbing. That water may not clear and you could have damage.

Winterizing isn't really difficult, just connect a hose to the faucet in the laundry center, put the other end of that hose over the drain and turn on the faucet. When it "runs pink", close the faucet and do the other one. That way you'll "know for sure" that the plumbing is protected.

If you're sure you'll "never/ever" connect a washer, you might consider locating those two T's and putting a 1/4 turn valve on each. That way you can eliminate any water into the laundry plumbing and not have to worry about it again. If unsure, just winterize those lines to be sure you have no leaks next spring.....