Hi I have just sold an old house near

You should have the Rendita catastale value, from that the IMU cost can be calculated, along with fines for late payment.

Thanks Steve, I have this so far- it was the fact they tax the stables at all I was surprised about, and the fact that the 2 similar values are for 2 different categories- both stables are approx 80m2 each and the house was 200m2. Its not making much sense to me really. I tried the site for cadastral values, it didnt recognise my codice fiscale, which may be because I no longer own it. this is 1 years figures.......they say they will let me off the penalties if I pay within 30 days. I gave the figure without extra penalties -that would take it to 7.7k euros. I will pay what I have to, just would like to understand the rationale.  CATEGORIARENDITA €IMU DOVUTA €   C02122.92156.94A04133.25170.13A04421.95538.75    

It has been a while since I looked at such things, but if you put your figures in here  I think you will find for 2017 alone there would be ove 1,200 to pay. I think I am right in saying you can just add the Cat A&C together as they are at the same rate for the calculation. There is no TASI for either that year, perhaps there was for the earlier years or the rate was higher. Someone else here might have a better knowledge to correct me.

Jude , you say that stables are noot abitable - but from yr's  visura catastale , have a Rendita -For not pay , your's stables has scheduled as F / 2 - unità collabenti   ( not  habitable )see >  https://www.amministrazionicomunali.it/docs/pdf/categorie_catastali.pdfFor the amministrazione comunale It does not matter what you think, but what the landlord understands -Pay Quiet ... Italy needs people paying taxes... :) 

Your visure show 2 houses and a deposit/store - all of which are eligible for IMU and TASI.  If they were unused and not those things then it would have been up to you to turn them in D/10 or unita colabenti which would have had a lower rate or exemption - depending on your comune.