When I first rented, i was SO naive on this issue. I eventually talked with a lead inspector, and it was eye opening. What I learned:

(1) BASICALLY ALL houses/units that are sufficiently old and haven't been remediated have lead. I naively thought that any lead issues would be solved in a big remodel. NOPE! The older a house is, the probability of it having some lead approaches 100%.

(2) For example, original windows are one of the most problematic/dangerous (opening/closing window or doors grinds lead paint -> lead paint dust contaminating all the surfaces/wood around it).

(3) Buyers, real estate people etc... view a positive lead test as a scarlet letter. NO ONE TESTS FOR LEAD because NO ONE WANTS A POSITIVE TEST ON THE PERMANENT RECORD. People take no test to mean may not have lead, but it's closer to the opposite!

(4) It's not obvious where lead is or isn't until you get an inspector and they use the scanner.

(5) The way lead home tests seem to happen is that a kid will have elevated lead on a routine blood test, THEN the home will get inspected, and then a remediation process starts.

(6) Real estate agents etc... will straight up lie to you.

(7) Sellers won't accept your home bid etc... unless you waive your right to test for lead before closing. (Even though that's illegal.)

(8) Most everyone seems to ignore or pooh pooh the issue.

(9) I'm not an expert. Everything above may have serious errors (i.e. go talk to a real expert, not me)!