Well, with trips back and forth to Bangkok, I slipped on paying my water bill. Too late to pay it at 7-11. A cashier at 7-11 said I had to pay at the water department's main office. She said it was somewhere near Tesco-Lotus on the super highway. I'm assuming she's talking about the Tesco-Lotus close to the northeast corner of Old Chiang Mai. Can anyone help with more specific directions?

On the superhighway, get over the Ping river going West, take the 1st slip road - the one you'd take to Tesco's and almost opposite where the sliproad meets the frontage road is the water company. There's a bloody big water tower in the grounds if you're not sure!

I'm assuming she's talking about the Tesco-Lotus close to the northeast corner of Old Chiang Mai.

Yep, as millwall says, it's the Tesco just over the river, which needs a bit of deft driving when coming across from the slip. Says 'Water' something or other in English and Thai. As you go through the gate, go immediately right and park in front of building. You pay in the office just inside and on the left. Pretty efficient in there.

It was easier to find than I thought. Thanks for the help!