If this doesn't do it, I would say the odds are a) it's defective, b) they are trying to get your goat, or c) they really need a regular flow shower head.

The single-family inventory I'm seeing at the $400k price point typically needs a lot of work and many of the defects are safety issues that could get a landlord in hot water if they weren't addressed in a timely manner.  

AND they are often held liable for failure to disclose "reasonably discoverable defects."

My tenants would pay for the repairs of all appliances, unless it needs to be replaced or defective.

They claim this is not a new defect, that we were aware of the issue due to the inspector's report. 

Even if the builder has an owner's policy there may be defects or liens in/on the title and you won't be an insured so you can't make a claim. 

“Virtually every FPE Stab-Lok® panel installed in homes today contains circuit breakers that are seriously defective, and the panels should be replaced.

This is how you end up with neighborhood secret police turning people in for putting trash out too soon or “visual defects.”

I hate to say it because you seem to be kind of on the ball, but it appears to me this is some significant defect in decision making capacity of things.

"A buyer wants to make sure they are clear about what they are purchasing, defects and all," he says.