It will probably need about an inch a week. It's generally best to give all of that in one day, but in the hottest part of the summer, it may work better to give 1/2 one day and 1/2 another day.

You can definitely water too much. Watering too much can lead to fungus, shallow roots, weeds, etc.

Thanks, that is what I thought. Two follow up questions thou.
1. If it is best to water all at once, why do many of my neighbors have their sprinklers run nearly every night?
2. When freshly seeding (or overseeding), is it best to water frequenty (daily?) for the first couple of weeks?

>"1. If it is best to water all at once, why do many of my neighbors have their sprinklers run nearly every night?"

Never confuse activity with accomplishment.

Always deep, infrequent watering. Your lawn needs one inch of water per week including rainfall. Using tuna cans placed in various places, run the sprinkler to obtain one inch of water in the tuna cans and time it. Run the sprinklers each week for that amount of time in every section to achieve one inch of irrigation all over. One inch will moisten the soil to a depth of 6-8 inches. This encourages the roots grow deeply. The soil will pull the water downward. The roots will grow down looking for water and nutrients. Each week, be sure to take rainfall into consideration.

>"2. When freshly seeding (or overseeding), is it best to water frequenty (daily?) for the first couple of weeks?"

follow this irrigation schedule after planting your new seeds.

water 15-20 minutes twice a day for two weeks
water 20-30 minutes once a day for one week
water 30-45 minutes once a day every other day for one week
water 30-45 minutes once a day twice a week for one week
move into deep irrigation, increasing the time to provide 1 inch of water all over and decreasing the frequency to just once a week. If you have to move the sprinklers at any point, the new location also receives 1 inch.

After seeding, baby the grass by staying off for 1-2 months. Mow when the new seeds reach 3 inches and mow it back to 2.

one inch of water per 1000 sqft is 600 gallons. If I had a lawn that size, it can get expensive in a hurry for me in Texas as it sometimes doesn't rain for weeks. Ir may take a lot longer than you think to achieve 600 gallons per 1000 sqft. You wouldn't believe that every single person looked surprised or confused when they asked me how often I water my lawn. I told them every 7 to 21 days. They thought I water 3 times a week because my lawn looked nice. It's all about deep watering but you have to understand what it really means to water deep.

I am in Eastern NC, as bpgreen stated, you can definitely water too much. I put in a new irrigation system last year and watered too much, had terrible winter kill and brown patch as a result. this year i water 1 inch per week at one time. I have several zones and some zones take longer and some take less time. All of mine vary. I also have centipede, St. Augistines and Zoyzia, all have different requirements. Depending on amount of rain, i alter watering schedule so as not to waste water.

>"1. If it is best to water all at once, why do many of my neighbors have their sprinklers run nearly every night?"

Never confuse activity with accomplishment.

Bwahahahahahaha! Good one, Gary.

There are two reasons why your neighbors might be doing that.
1. The guy who installed the sprinkler system set it up that way and nobody ever changed it. Sprinkler guys LOVE that setting. It demonstrates the sheer genius of their installation.

2. The guy who planted that original seed set it up to water three times per day for 10 minutes each. That is normal. Then, when the grass came in, the homeowner wanted to get back to something normal so he/she reset it to water every day for 30 minutes (sum of the daily watering for seed). Seems logical but it is not a good idea.

As we all know, frequent watering is required for seed germination. The seed and soil surface should be moist at all times. If you continue to supply water like that, every (weed) seed that flies into your yard will germinate. However, if you let the surface of the soil go completely dry between waterings, the (weed) seeds will not germinate.