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Help your owners save on property tax.

We review and appeal your owners' property taxes every year. Owners pay nothing unless we win.

Become a referral partner → Book a call

Your owners' largest controllable property expense.

~1/3

of a multifamily building's operating costs is property tax. For income property, that's about 20–35% the size of NOI.

15–40%

typical reduction for the cases we take and win. On a $10M apartment building that is roughly $20,000 to $80,000 a year, depending on the state.

What your owners get

Monitoring

Checked every year

We check every building against the county's records each year.

Appeal Autopilot

Appealed when there's a case

When there's a case, we build it, file it and argue it. Owners pay only if we win.

Convenience

No paperwork for owners

You share the records you already keep, so owners don't have to.

Why Castellan

  • The detailed work, every time.

    Most firms check value per square foot and a few nearby sales. We do the labor-intensive research on every building.

  • Technology plus decades of experience.

    Our software combs the county's records. Our team brings decades in property tax.

  • We find what others miss.

    • Rent-controlled units valued as if they rent at market rates.
    • A garage or storage space counted as living area.
    • A case built from comparable buildings' financials.

How partners work with Castellan

01

Sign the partner agreement online.

About five minutes. Nothing is owed by anyone until we win an appeal and collect.

02

Send us your owner list.

Upload your property and owner directories, rent roll and operating statements through your private upload page.

03

Share the owner invitation.

Every owner on your list gets a personal introduction to send from your own email as soon as your list is in. When our review finds a case, we add a follow-up note for that owner.

04

Keep your fee, or pass it on.

For each owner's first year, earn 20% of our fee, or pass some or all of it to your owner as a first-year discount.

Questions

Does this make me a tax agent, or need a license?
No. A tax agent is someone who communicates with the county on an owner's behalf, and you never do. Referring a client to us is not an act that needs a real estate license. You do need to tell your owner, in writing, that you receive a referral fee. We make that easy: it is written into the owner's agreement, and we give you the sentence to use.
Does my owner pay more because you pay me?
No. Your referral fee comes out of our fee; it does not change the owner's rate. If you choose to pass some or all of it to your owner, their first year is that much off our fee. Our rates are on the pricing page.
What if an owner already has an appeal firm?
They don't have to choose. An owner can keep their current firm and sign up only the buildings they want us on. We're also happy to take a second look at buildings their current firm passed on. A fresh look sometimes finds a case others missed.
Do we need to wait for a case review before inviting owners?
No. Once your owner list is uploaded, every owner on it gets a personal introduction you can send right away from your own email. When our review finds a potential appeal for a property, a follow-up note for that owner appears on your page.
What happens in later years?
The owner stays on monitoring: we check their assessment against the county's records every year and appeal again whenever it is worth filing. Each January we ask you for the prior year's rent roll and operating statement, due March 1, so we can file on time.
Can an appeal raise an owner's assessment?
In some states a board can raise a value as well as lower it. We only file cases the county's own data supports, and we tell the owner before any hearing if we think that risk is real. The owner can withdraw at any time before a decision.

Sign up as a partner.

Sign the partner agreement online and send us your property list. We prepare owner invitations and coordinate outreach with you.

Become a referral partner → Book a 15-minute call
Emailinfo@castellan.so

Referral terms are set out in the partner agreement. Each owner's fee terms are provided to that owner in writing before any filing. Nothing on this page is a guarantee of any outcome.