Rates for watering plant and shrubs

[jarabe1]

Hello, I need help. I have to bid on a landscape installation project. I do lawn maintenance for this subdivision and they want me to water this plants once a week after installation. I have a 300 gallon hydroseeder that I can use but have no Idea about pricing.
I'd say it will take at least 30 to 40 min but there is more time involved like filling up the tank & transportation. Thanks in advance.