Q: Supplemental Tax Bill doesn't add up

Hello all,

I bought a new construction condo and closed escrow last year November. Just got my supplemental tax bills (x2) but the total amount is higher than I expected it to be.

One tax bill is for the land between COE and 7/2016, and another is for building+"land value increase" between COE and 7/2016. Each bill has 3 taxes calculated on its respective value: Basic Levy Rate (1.00%), Metro Water (0.35%), IRWD (2.8%). No references to any Mello Roos on either bill. The total tax bill is ~$3000.

At COE, I paid a prorated County Property Tax of ~$4000 to escrow (prorated from COE to 7/2016). That + the total tax bill would be a sum of ~$7000.  My annual total tax including Mello Roos should be ~$8400. Prorating it from COE to 7/2016 should be ~$5600, which -$4000 from escrow, I expect the supplemental tax bill to be ~$1600.

Any idea? Did I do the math wrong? I probably will need to make calls on Monday to figure out what's going on, but I'm not even sure who to call first: County, Builder, Escrow?

Many thanks in advance.

Sounds like the county has assessed your property higher than what you originally paid. You can appeal if you want. I would call the county if you have questions. Mello Roos is a fixed amount which is why you wouldn't see it on your supplemental bill. I assume you paid all your annual MR via escrow.
http://ttc.ocgov.com/proptax/supplementaxbill

Thanks Rizdak.  County did assess the land higher but it wasn't by much (not enough for the supplemental tax bill to increase by 100%).

In the end, I was able to resolve it with the builder.  I e-mailed them, and they helped me breakdown what taxes I paid at close of escrow. Essentially at close of escrow, the taxes I paid for covered the property tax for the land only and all Mello Roos.  What I owe should be the tax assessed on the building.  However, County sent me supplemental taxes for both the land and the building.

The builder will pay the supplemental tax for the land since I have already paid that to the Builder at COE. My responsibility will only be the supplemental tax for the building only.