I concur with drpete. The main may be 4ft in the ground but there must be a place before the line enters the house that you can dig down to and tap. A 1/2" line is most likely too restrictive and will short you on flow. Remember, a 1/2" line is only "half" the size of a 1" line but it carries 25% as much water NOT half. Hose bibb connection should be an absolute LAST resort. In addition, you would need two backflow devices. That additional cost would far outweigh even having it professionally du...
