I saw this on Friday and I didn't have time to say anything.
I think there's a slight miscommunication here so I thought I'd just put my two cents in.
First, most people think of the water coming out of their tap as 'pressure', when in fact it's flow rate.
Best example I found is this:
Think of a syringe. Now fill it with water. If you don't push the end the water won't move. However, depending on how fast you push the end, the water moves at that rate. The pressure does not change however. Just the rate of flow.
The next part of the confusion here is your description of 'slope'. If the pumps that supply the flow rate are not working and you're at the top of a steep slope then you are unlikely to get any water. Unless you have a siphon system the water isn't going anywhere. Unlikely that you would have a siphon system btw. So pumps are required to push water uphill. You cannot gravity feed water uphill unless there is some sort of flow already. If the pumps are not working and there is no bypass system for the water then you will not get any water. Also, if there is a bypass, further uphill you are from that flow, the less likely you'll have water.
To add to this conversation (though long gone now), living in Australia during a drought we had water restrictions, though we managed to have water still. My wife who lived in various parts of Australia had times when there was no water. Also when I lived in Toronto we had water shortages due to the processing time.
Such is modern life.