I always suggest that people keep all plumbing lines out of bale walls. Sometimes this is not possible and water lines need to be run through bales. The most common example of this is with hose bibs. Frost proof hose bibs need to be run back into the wall about a foot or so. For that reason, and also per our local plumbing code, we cannot place them on exterior stand pipes outside of the structure. In order to keep the risk of water leaks out of the bales, I build water line isolation walls which completely separate the bales from the pipes.
A simple construction of 2×4’s, plywood, and roofing felt, the boxes or wall sections (depending on the hose bib location) are open directly to the gravel bed in the toe ups. This allows any leaks or condensation to make its way to the drain rock.
I also use these walls around shower valves when a shower is inset against a framed 2×6 exterior wall that squares off to two bale walls on either end. In some cases, the shower valve will end up outside of the bale wall but the hot water “in” line will be within the plane of the bale wall. I place plywood and 2×4’s so that if the fitting/union at the valve ever leaks, the water cannot spray into the bales. Instead, it will hit the plywood or 2×4 (both of which are covered in roofing felt) and drain to the toe ups below. A little caution and forethought can go a long way towards creating a well built home.