I wouldn't risk feeding a cat milk, lactose or not. Humans are still adapting to dairy after all! Have you considered running water? Cats naturally get their water from their diet this is why wet food is recommended for 50% of their diet. They sell pet fountains quite cheap now a days. You can test it on a cheap decorative fountain to see how it goes before buying a pet one.
Thank you. Yes Smudge will drink out of pots in the garden where rain water has been standing for a while, and like I said, the bird bath! Yes our water does have chlorine, so I can understand why he does not like it, that is why there is a bowl for him in the garden with rain water.
Love the story of your 5 cats Annie. Cats know what they like. I have semi skimmed milk so will give him some now and then. It is I worry as he loves dry food, and I know cats should have liquid. I do give him wet food too.
Kitties often prefer water that has been standing a while that seems to us a little brackish. My cats often drink the bucket water outside and turn up their noses at water from the tap (no chlorine). So it might be an issue with the flavor.
As Opus says, some kitties love cow's milk. We have four barn cats and a house cat. Of the five, one would kill for half & half. (He knows the word "Cream?" and runs to the fridge if you say it). He won't drink milk, though. One will drink half & half if offered but doesn't get too excited. The others won't drink any (cow) dairy product, though one of the others is fond of butter. I had heard butterfat and cream will give a cat the runs, but have never seen this. In short, cats do have their preferences and usually stick with them, but I don't know if that is because they can't handle lactose or if they just don't care for the dairy products.
maddie, not all cats are lactose intolerant, some can drink milk without issues...
do you have chlorine in your drinking water? perhaps thats why Smudge prefers rain water...
can you collect up rain water and bring inside for him so he always has some available?