can you over water a lawn
When watering a new lawn, use just enough water to keep the soil moist at seed depth. Standing water or prolonged heavy rain could ruin some of the seed or possibly wash the seed away. If overseeding a lawn where you have established grass, be sure to keep the seed moist by watering lightly twice a day. Occasional deep watering is okay to maintain grass health. The existing grass will help keep the seed in place, shade the soil, and slow evaporation.