Husband's potential liability depends on the nature of the legal relationship between him and the home owner.
If husband is an independent contractor he is liable for his own negligence or that of anyone working for him.
He might try and contract out of liability in whatever contract he makes with the customer - not popular with customers or courts.
Also, as a general principle, a principal [householder] is not liable vicariously for the negligence of an independent contractor.
If husband was a direct employee of householder the H/Holder will be liable vicariously to any other party injured by husband's negligence.
However, in that scenario, the H/Holder can actually seek indemnity and contribution from husband.