US officials are now asking themselves why the hackers, who struck during a scorching heat wave, didn’t go further in causing damage at the water facilities. The soft underbelly of American infrastructure — local water and power plants that serve military facilities, for example ­— have been targeted. Now, water system operators in modest-sized towns and counties are at the forefront of investigation into one of the most serious cyberattacks on the sector in years. Kathy Hochul, a Democrat, has announced about $9 million in grants to try to strengthen the cyber defenses of water systems across New York. Democratic Sen. Adam Schiff of California plans to introduce legislation next week that would give the Environmental Protection Agency’s greater authorities to help boost water cyber defenses, Schiff’s spokesperson told CNN.