On Tue, 24 Jan 2017 16:12:08 -0800 (PST), trader_4
wrote:

If the battery pump can keep you safe long enough to get a new AC pump,
that would be good enough reason for me to keep doing what you're doing.
I'd have the battery pump set to come on at a higher level and also an
alarm set up to sound so that you know the primary pump has failed.
They have cheap $10 alarms for water heaters at HD and similar. May
be loud enough and work for your purpose.

Why would you put an alarm on a water heater, and where does it connect?