In California, and probably other states as well, you would have to disclose this party house when you sell

What, exactly, would you be required to disclose? That a neighbor has a lot of parties?

Yup:

California's Stringent Disclosure Requirements

California sellers must fill out and give the buyers a disclosure form listing a broad range of defects -- such as a leaky roof, deaths that occurred within three years on the property, neighborhood nuisances such as a dog that barks every night, and more. In addition, California sellers must disclose potential hazards from floods, earthquakes, fires, environmental hazards, and other problems, in a Natural Hazard Disclosure Statement. California sellers must also alert buyers to the availability of a database maintained by law enforcement authorities on the location of registered sex offenders.

That doesn't say anything about disclosing information on the neighbors' activities.

neighborhood nuisances

It's the end of the world as we know it, and I feel fine

So all you have to tell them is that a lot of cars park on the street on weekends. You wouldn't have to say why.

-So...you get a lot of cars parked here on the weekend.  Thanks for the heads-up.  What are all of those people doing?

-ummm, Scrabble?

It's the end of the world as we know it, and I feel fine

So all you have to tell them is that a lot of cars park on the street on weekends. You wouldn't have to say why.

But the minute they found out what was going on, you'd have a hard time proving that you didn't know. And they could sue you.

I went through something very similar recently when we sold. We knew that a house across the street was about to be licensed for some kind of residential board and care. We tortured ourselves over whether to disclose, which we finally decided to do after the fact, in escrow.Thankfully, the buyers didn't care or didn't care enough to back out.

In California, the advice is that if you're wondering whether you should disclose something, then you should disclose it.

the minute they found out what was going on, you'd have a hard time proving that you didn't know

Is that really how California courts work? If someone sues you you must prove you didn't know something rather than the plaintiff proving that you did?

It's a matter of shifting burdens. The plaintiff merely has to establish that the "party" problem existed when you were living in the house and argue that it is unreasonable to believe that you were unaware and that you knew or should have known.

It's not a matter of absolute proof that you knew; it's a question of whether the judge or jury concludes that you must have known, and the standard of proof is a mere preponderance of the evidence in civil court.

So in California, you had better say that during a neighbor's Friday and Saturday "parties," there are blocked roads, excessive traffic, and parking problems.

So in California, you had better say that during a neighbor's Friday and Saturday "parties," there are blocked roads, excessive traffic, and parking problems

I thought you were suggesting that the, um, adult nature of the parties would have to be disclosed.

To your "What, exactly, would you be required to disclose? That a neighbor has a lot of parties?" I had answered with a linked "Yup."

But you bring up an interesting question. If I were aware of the nature of the parties, would I have to disclose that? I had been advised to disclose that that house near us was now licensed as residential board and care, not just that there may be increased traffic or parking problems.

So I don't know just how far one has to go to define the particular "nuisance."