Appreciate all who offered battery replacement pointers!

I needed one *today* & thus had only Napa & the big box stores to choose
from.  I opted for Walmart--2 yr replacement
&  $39.99 installed.
Napa wanted $83 for an Exide, but wouldn't install it.

When they pulled the old battery, there was water in the compartment--maybe
3 tablespoons.  It's been raining
all day--but I am hard pressed to know how rain water got there.
Should I be concerned?

Phaedra
'85 Wolfsburg Westy "Hester"