Managing squalor?

So how do I combat squalor? Is it a matter of matching farming production with population or something else. And if so are there any figures out there. I'm plagued by revolts at the moment and it's squalor at the heart of it

Squalor is far less of a problem in M2TW than in Rome. There really isn't much you could do really; only town administrative buildings can help to combat squalor in Western factions (The muslims and ERE get other faction unique buildings that deals with it). When it get out of hand you might as well just masscre the populance and start again with less population. That method is by the far the most effective at dealing with the problem of squalor (make sure the city is already upgraded to huge city though). Even though I never really had to do that in any of my M2TW campaigns, in Rome that sort of thing happens all the time.

In a nut shell; just build Inns, churches and other happiness buildings to balance it out, or increase garrison/lower taxes. Bloodwash the city only if you have to.

It's easy to get carried away concentrating on advancing your military buildings to recruit elite units, but as you're experiencing, if you don't look after the "little guy", he's going to revolt... if living conditions are bad, you won't have any population growth, impacting on your ability to recruit more troops - and worse case scenario, you lose the settlement because it turns rebel.

In addition to farming, there are civic buildings that need to be built (Council Chambers etc) that directly address squalor & sanitation and determine the living standards in your settlement - and religious buildings, inns, brothels, fairgrounds and marketplaces also help to reinforce population loyalty and happiness. I'm not up-to-speed with all the "techie" stuff in the game, but the advisor button on your settlement card activates the built-in advisor that appears in the top left-hand corner, who will give you the sequence to build in order to maximise the welfare of your citizens.

No wonder I have issues with squalor. I tend to build up to the basic brothel and inn plus market place. Churches I go a little further to please His Holiness.

I usually sack a settlement when taking it, if it is of the same religion and exterminate if of a different one (unless I intend to sell all the improvements and give it to the Pope or an ally). Then I normally try and get it to grow asap. Revolts are unheard of unless a very high level chivalrous gov. dies and I am too lazy to notice when the city turns red (which happens about never). But do not neglect to construct some administrative buildings and try not to get excommed. unless you really have to. Bigger walls always helps.

You don't 'combat' squalor, it's merely the mechanic that maintains the growth balance of cities and ensures you can't just build every single growth structure you can and roll around carefree in the vast tax revenues of your hellish medieval metropolis.

Squalor just does its thing regardless, it's up to you to build structures that will maintain a balance. Don't bother and your city will either stop growing entirely or become unhappy....which is perfectly reasonable. It's worth taking note of the fact that the 'health' bonus many structures supply affects happiness and growth equally. A 15% health bonus equates to 15% happiness and 1.5% added growth, and as such it can often be serious overkill to max out the farms in a city, since those health bonuses (especially from the city council/government buildings) are enough to get the job done of getting the city to the 24000 population 'Huge' point with only one or two farming upgrades. In fact, the government building line is the most important by far, since the health bonus provides happiness and growth, on top of the additional happiness that same structure provides through its law and order bonus, and as such is the very best growth/happiness balance in any structure you can build. It's seriously cheap as well!

Maintaining that balance is key, since the majority of the time you'll find that a city can easily stack up much more growth with its structures than it could ever maintain with its various happiness structures. And farms can't be demolished, so if you've completely stuffed up your growth to happiness balance, there's nothing you can do about it except watch the squalor build up and up and up until the riots break out.

Distance to capital is also a huge b*****d to watch out for. The Egyptians haven't got a problem building Irrigation in Cairo, because it's one of their homelands and they can keep control of a much higher population. Then you come along screaming something about 'the one true God', murder anyone who looks at you funny, and suddenly find yourself with a city that has a 65% distance to capital happiness hit that just won't stop growing!