Weird lines in grass

First time owning a house with a septic. We are in our second year in this house. We've lacked rain, this year. We've started seeing these brown distinct lines in our yard. I always thought a septic might make your grass GREENER, not brown. Curious what is causing this.

https://preview.redd.it/1tcny3pyipdd1.jpg?width=2580&format=pjpg&auto=webp&s=21538c599ae3fef6954f6181372853b9e1011d70