High TA in fill water

[AndyJ]

I got a sample of fill water from a friend to test for iron. I ran a full set of tests to see where he would be starting. Here are the results:

pH 7.7
CH 280
TA 400
FC <0.2
CC 0.2
iron 0

All of these seem reasonable to me except TA. I'm wondering if the collection technique or transportation could have a big affect on the quality of the sample. He said he got it from the hose which will be filling the pool, but it was the water just sitting in the hose (he didn't let it run first). Also, I got it in a glass Kerr jar with a 2-part, vacuum-seal type lid (I think it's a standard jelly jar). It was probably in there for at least 10 hours, maybe as much as 24 hours.

Should I ask for another sample, perhaps directly from the spigot? And in a plastic bottle? Or is a TA that high possible from a city water supply?