I've seen people with shallow water dishes with marbles in them so the chicks don't down. I don't know if my broody could drink from/get enough water from one.
Maybe you could do a bottle with a chicken nipple for mom? Who knows, maybe even the chicks would drink from it. I think I have read of people using them from day one. Or else use a waterer and put some river rocks in the red trough part. That is what I did when my chicks were in the brooder till I thought they had enough sense not to drown themselves in it. Mom could drink all she wanted that way.