This particular phrase, uttered by legions of law enforcement officers across California (and the rest of the US) whenever they don’t want to do their job, is one of the most irksome, irritating, and completely abused phrases in the law enforcement lexicon.  This stock phrase is used because most people don’t know what the law is, and law enforcement know it-so they use it.

For example, when a single tenant occupies a room in a house that you occupy yourself, you do not need to go through the process of filing a eviction lawsuit (aka unlawful detainer).  You simply give them a 24-hours notice to quit, after which not only can they be evicted, they are committing a criminal act by staying.  See Civil Code Section 1946.5, Penal Code Section 602.3.

The reason is because the individual is not a tenant, but is classified as a lodger.

I have run into exactly this kind of situation, and the police have refused to remove the individual.  It is extremely frustrating to have law enforcement fail to enforce the laws which are clear and unequivocal on their face.  It is conceivable that this phrase “It’s a civil matter” may eventually lead to a lawsuit against a  law enforcement agency.