As

Yes, that sounds reasonable.

I think both are possible, and the meaning/context determines which one is to be used. Also, I don't think switching the underlined part as you mentioned affects which one is to be used.

However, and guessing at the meaning you may have in mind, I beleive like is the one to use:

We shouldn't waste rainwater like people in that country do.

Good. One more related question, MM.

What it the difference between these two?

I don't use money like he does.
Like him, I don't use money.

The first one is awkward: use 'like he does'.

I fixed it.

Now, what is the difference?

I see no real difference, except that the point of the utterance comes at the end of the sentence.

Isn't the difference that the first one means that the way I use money is different from his way but the second one means that neither he nor I use money?

Oh, yes. That sounds good. What did you ask us for, then?

Oh, yes. That sounds good. What did you ask us for, then?

I thought this would also work as 'We shouldn't waste rainwater as/like people in that country don't':

As/like people in that country, we shouldn't waste rainwater.

Ah. Well, it seems not.