He did not set out to hurt her. He probably passed by a dozen objects far more capable of causing harm than a hose. Pens, staplers, frames for art, a statue, hell even his fists are all more harmful. I struggle to think of something that causes less harm than tap-pressure water. I would say he explicitly set out trying not to cause any harm, or he would've reached for a more obvious and harmful option.
Neither of us knows what his state of mind was, but I don't see anything outright implying contempt. Doing something bad to someone doesn't require contempt, it can be a practical means to an end. Based on him calling social services, I would say he didn't have contempt, he just realized the government wasn't going to help and took it into his owns. Similar to managers when they have to fire someone; doing so doesn't imply or require contempt, it's just a means to an end.