Great to hear all the replies! I should mention that most of these house concerts are not really advertised in the way it would be if the concert was held in a small venue, hall, club or coffeehouse.

Some of the houses are not always that large. I'm going to a house concert this Saturday and they will be having one in the afternoon at 2 PM and another in the evening at 7:00 PM. The people that attend these concerts are very well mannered, respect neighbours and do not get drunk or anything. They just want to hear the musician/singer who is performing, meet the artist and talk to other people at the house concert. They are the type of people who do not get rowdy or loud after the concert (when walking down the street to where they parked their car.)

Of course the concerts draw usually a more reserved crowd as the music is folk and very acoustic oriented. I would say the
majority of people attending most house concerts are over 40 or 45 years old (there is always exceptions - but most seem to be around middle-age or even older. I'm not saying that these house concerts may not encounter a problem now and then but for the most part people attending are very respectful. I have never seen anyone who was drunk or acting obnoxious at these house concerts.

Many people often bring a pot-luck dish such as a salad or casserole. Also,I see that people take their garbage to the kitchen and throw it away themselves and do not leave their food dishes for the owner to collect. So..all in all I have not seen any problems at house concerts I have been to and I have been to a lot since the 1980's.
I would imagine though that the owners of the house have to have a certain type of insurance on their insurance policy in the event someone should fall or get hurt. I have not personally heard of it happening though. There could be anywhere from 15 people up to about 30 people attending on the average (depending who is performing).

You do have to make reservations by phone or email so the owner knows how many people are coming so that is why you don't see flyers around town advertising house concerts. It's kind of word of mouth or the artist's website. On the artist website it will usually just say "House Concert" the date and city with a phone number to call for information (but not address). Then you can pay when you arrive at the house. (average about $10.00 to $15.00 a person) which majority goes to the artist or artists.