two water lines

Does it leak when using only your onboard pump? Do you have a pressure regulator attached? Occasionally city water pressure is much too high.

If that is not the issue, you get to start tracing the line and examining each fitting until you find the source of the leak. :-)

The come out and drip on the ground?

Low point drains, there shoudl be valves above them, One of the valves it seems is not fully closed.. Common valves, not special made in most cases though there are exceptions to that.

May be low point drains, one each for hot and cold water lines. Do you have any valves in a compartment for low point drains? One of the valves may be leaking.

If it is a drain valve leaking some styles have a small stainless steel clip that when removed lets you pull the valve stem out and replace the O ring. If it's running down the outside of the pipe from a joint farther up you may have a leaking fitting. Depending on how difficult it is to access you may be able to repair it with shark bite type fittings and more pex pipe. They are more expensive but work well in confined areas.

I think its the cold water low point valve not seeling all the way. On my 86 motor home i often had to ush then twist to seal all the way.