PTAX-350, Uniform Application for Assessment of Affordable Rental Housing, is the Illinois Department of Revenue form a property owner completes to have a property assessed and considered for classification as affordable rental housing units. Rock Island County posts the form on its website, which is why it turns up in searches for the Rock Island County assessor; the form is completed annually, and the county's listing gives July 1 as the 2026 filing deadline. On this page you can fill out the form online on FillingPDF and download or print the completed PDF; the official PDF is published by Rock Island County at the source link below.
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What is PTAX-350?
PTAX-350 Uniform Application for Assessment of Affordable Rental Housing is the Illinois Department of Revenue form an owner completes to have a property assessed and considered for classification as affordable rental housing units under 35 ILCS 200/10-235 et seq. and 35 ILCS 200/15-178.
The form is built around a program option. After the applicant, parcel and project blocks, you select one of four options, each with its own terms printed on the form:
- Option A requests income approach valuation only and requires Schedule IV, Income and Expenses.
- Option B1 covers 15-35% of units at or below maximum rent for at least 10 years (25% reduction of assessor AV).
- Option B2 covers 35% or more units at or below maximum rent for at least 10 years (35% reduction of assessor AV).
- Option C covers 20% or more units at or below maximum rent for at least 30 years, on a graduated scale described in the instructions. The form notes that it is not available in all areas and tells you to consult IHDA.
The project block also records whether the application is for New Construction, a Qualifying Rehabilitation or a Recertification, and an applicant who meets the affordability requirements through an income-based subsidy program can select Section 8, Section 42, Section 515 or Other. The form states that it is to be completed annually and that incomplete or fraudulent applications will be rejected and may be subject to additional legal review. Rock Island County publishes the PDF, but the form is an Illinois Department of Revenue document, not a county-specific one.
Who needs to file PTAX-350?
Owners of rental property who want it assessed and considered for classification as affordable rental housing units under 35 ILCS 200/10-235 et seq. and 35 ILCS 200/15-178 complete this form, along with the schedules that apply to the option they choose.
Conditions printed on the form:
- The application is completed annually, so an owner who already has a project in the program files again each year and may select Recertification.
- An owner whose property has several parcels selects Multi-parcel, leaves the Parcel Identification Number blank and attaches Schedule III.
- An owner whose affordability requirements are met through an income-based subsidy program selects one of Section 8, Section 42, Section 515 or Other (with a description).
- An owner interested only in an income approach valuation selects Option A and attaches Schedule IV.
- Option C is not available in all areas; the form tells applicants to consult IHDA.
The form lists an owner name and a primary contact, but it prints no rule about who may sign for an owner or act as a representative.
When to file PTAX-350
Rock Island County posts this form under a title stating that the filing deadline for 2026 is July 1, and the file name gives the date as July 1, 2026. The form itself says it is to be completed annually, and it carries an Application Year field, so a new application is made for each year. An owner whose project is already in the program can select Recertification in the project block. The form also prints durations tied to the options: Options B1 and B2 require units at or below maximum rent for at least 10 years, and Option C for at least 30 years. The form sets no processing time. For deadlines in other years, check the county's Documents & Forms page and the instructions the form refers to.
Documents you need
- Schedule III: attach if the property has multiple parcels (you select Multi-parcel and leave the Parcel Identification Number blank).
- Schedule II: attach if you select Qualifying Rehabilitation as the project type.
- Documentation of all construction costs: attach if you select New Construction.
- Building permits issued by the local municipality: attach with the construction documentation if you select New Construction and permits were issued.
- Schedule IV, Income and Expenses: attach if you select Option A, income approach valuation only.
- Other schedules and addenda indicated on the form for the program option you select (B1, B2 or C), as the form directs and the instructions explain.
How to fill out PTAX-350
Enter application year and owner
At the top of the Applicant Information block, enter the Application Year and the Owner Name.
Enter address and parcel number
Enter the Property Mailing Address (Street/PO Box, City, State, ZIP) and the Parcel Identification Number. If the property has several parcels, select Multi-parcel, leave the parcel number blank and attach Schedule III.
Add primary contact details
Enter the Primary Contact, Telephone and E-Mail for the application.
Complete the project information
Enter the cumulative number of units, total project size (sq. ft.), year of construction or qualifying rehabilitation and number of units in project at or below maximum rent (see the instructions). Add the IHDA Project Identification Number if applicable.
Select the project type
Select New Construction (attach construction cost documentation and any building permits), Qualifying Rehabilitation (attach Schedule II) or Recertification.
Choose a qualifying program
If affordability requirements are met through an income-based subsidy program, select one: Section 8, Section 42, Section 515 or Other. If you select Other, describe it.
Select your program option
Select Option A, B1, B2 or C after reading the eligibility definitions in the instructions. Option A needs Schedule IV and is marked no fee required; Option C is not available in all areas.
Complete the option line
For B1, B2 or C, complete the dollar line beside your option as the instructions direct. For Option A, no entry is needed on that line.
Gather schedules and addenda
Collect every schedule and addendum the form requires for your option and project type, such as Schedules II, III and IV.
Review and download the completed PDF
Check the application year, parcel numbers, units and selected options, then download or print the completed PDF from FillingPDF and assemble the package described under How to submit.
How to submit PTAX-350
The form names no submission channel: it says to submit all required application information, schedules, and addenda as indicated on the form for the program option selected, and it prints no mailing address, office or portal.
Assemble the package for your option:
- Option A: the form with Schedule IV, Income and Expenses; the form marks this option "No fee required".
- Options B1, B2 and C: the form shows a dollar line next to each option; read the instructions the form refers to for what applies.
- Multi-parcel properties: Schedule III.
- Qualifying Rehabilitation: Schedule II.
- New Construction: documentation of all construction costs and, if applicable, building permits issued by the local municipality.
Rock Island County publishes the PDF at the source link on this page and lists related assessment forms at https://www.rockislandcountyil.gov/179/Documents-Forms. Confirm where to deliver the application with the county before the deadline. FillingPDF lets you fill out and download the PDF; submission follows the agency's channels.
Common mistakes to avoid
- Entering a Parcel Identification Number and also selecting Multi-parcel; the form says to leave the number blank and attach Schedule III.
- Selecting Qualifying Rehabilitation without attaching Schedule II.
- Selecting New Construction without documentation of all construction costs and any building permits issued by the municipality.
- Choosing Option A without attaching Schedule IV, Income and Expenses.
- Selecting Option C in an area where it is not available; the form says to consult IHDA.
- Submitting an incomplete application; the form says incomplete or fraudulent applications will be rejected.
- Treating the application as a one-time filing; the form says it is to be completed annually.
- Selecting more than one qualifying program when the form says to select one.
- Missing the July 1 filing deadline that Rock Island County lists for 2026.
Frequently asked questions
What is Form PTAX-350?
PTAX-350 is the Illinois Department of Revenue's Uniform Application for Assessment of Affordable Rental Housing. An owner completes it to have a property assessed and considered for classification as affordable rental housing units under 35 ILCS 200/10-235 et seq. and 35 ILCS 200/15-178.
Is PTAX-350 a Rock Island County assessor form?
Rock Island County publishes the PDF on its website, but the form is issued by the Illinois Department of Revenue (PTAX-350, R-08/23). The form itself does not name a county office to receive it, so confirm delivery with the county.
What is the 2026 filing deadline for PTAX-350?
Rock Island County lists the form with the title "Filing Deadline for 2026 is July 1", and its file name gives July 1, 2026. The form says it is to be completed annually, so file a new application each year.
What is the difference between Options A, B1, B2 and C?
Option A requests income approach valuation only and needs Schedule IV. B1 covers 15-35% of units at or below maximum rent for at least 10 years, B2 covers 35% or more for at least 10 years, and C covers 20% or more for at least 30 years on a graduated scale.
What do I attach to PTAX-350?
It depends on your selections. Attach Schedule III for multiple parcels, Schedule II for a qualifying rehabilitation, construction cost documentation and any building permits for new construction, and Schedule IV for Option A. The form directs you to the instructions for other options.
Is there a fee to file PTAX-350?
Option A is marked "No fee required" on the form. Options B1, B2 and C each show a dollar line, and the amount is not printed on this page; follow the instructions the form refers to or ask the county.
Do I have to file PTAX-350 every year?
Yes. The form states it is to be completed annually and has an Application Year field. If your project is already in the program, you can select Recertification in the project block.
Can I fill out PTAX-350 online on FillingPDF?
You can fill out the PDF online on FillingPDF and download or print it. FillingPDF is an independent service, is not connected to Rock Island County or the Illinois Department of Revenue and does not file the application.
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