People think in dollars, not gallons. The dollarize value is based upon your average rate selected during setup, or your most recently entered water bill. Weekly dollarize displays your estimated average weekly spend based upon your provided bill information.
To learn about updating your water bill, read this article.
If you would like to speak to a member of the bluebot team, simply navigate to Settings > Support from within the app and choose your preferred method of communication. Otherwise, you can email firstname.lastname@example.org