One can create a beautiful “rain-only” lawn without using herbicides, pesticides, high-test fertilizer, and massive amounts of irrigation water. Simply apply weak organic fertilizer and lime in early spring and fall, cut the grass tall with a sharp blade, leave the clippings to decompose on the lawn, and rely on earthworms to aerate and enrich the soil.
I use this approach, which saves me a lot of money on chemicals and irrigation water. Here’s a photo of my lawn on June 18, 2015 under abnormally dry conditions.
Look closely and you can see the clippings from mowing the day before. Night-crawlers come to the surface at night and ingest decomposing grass clippings. They go back down into the soil during the day and poop. This increases the organic content of the soil, thus sequestering carbon. This has been going on for over 20 years, so presumably the soil under my lawn is higher in organic content than it used to be. The organic matter absorbs moisture when it rains, and releases it slowly to keep the grass alive during dry spells.
PS – This two-page water bill insert provides more details about the lawn management method I use. The photo on the front is my lawn.