Quote Originally Posted by Quirinus
So, in effect, it gives an extra number of people 'free' without the public order/pop. growth penalties of squalor?
That's the general effect, yes. If your settlement is stable in population and public order without a sewer, it will be similarly stable after the sewer (once population growth is done) only at a higher population. If your settlement is having public order problems without a sewer, the sewer won't fix them except in the short term - and if the public order problems are because of squalor, it will be a very short term indeed. Squalor tends to only be a problem in big cities, and 0.5% population growth from a sewer upgrade is a whole lot of people every turn when applied to a city with 30,000 souls or so.

Personally, I like to build sewers as my second choice if my city needs to grow more. First is trade buildings, of course - can't beat a trader or forum if all you need is 0.5 or 1% population growth and you don't already have one. But after that, I choose sewers. Only if trade and sewers aren't enough will I turn to farms.