Is your irrigation system’s timer set for the same frequency as it was during the summer months? If so, you should alter the settings to accommodate for the autumn climate.
While your grass still needs water during the autumn months, it doesn’t need as much as it did under the summer heat.
To update your timer, you can trim the amount of waterings each day, while making sure that your lawn still receives adequate moisture. Instead of multiple waterings, you can give your lawn less waterings for a longer period of time.