My child is 10 months old, is it safe for him to drink regular tap water?

Not recommended. Check with your local water utility. If your tap water is fluoridated or has substantial natural Fluoride (0.7 mg/l or higher), consider using a low-fluoride alternative water source. The american dental association recommends not using water that contains high levels of Fluoride when mixing powdered or concentrated baby formula. Too much Fluoride puts your baby at risk for enamel fluorosis.
Generally yes. Tap water quality can be very variable depending on where you live but if of good quality, 10 month old babies that crawl all over and get their fingers into their mouths and pick things from the floor an also put them into their mouths, are ready to drink tap water.