IRS NOTICE REFERENCE
Understanding your CP518 notice
This is your final reminder; we still don’t have a record that you filed your prior year tax returns.
General information only. Not legal or tax advice.
Notice details
- Notice code
- CP518
- Category
- Filing and non-filer
- Severity tier
- Tier 3 — Time-sensitive response. The notice carries a response deadline or may affect account standing if ignored.
- Governing law
- §6651; §6012 (Internal Revenue Code sections)
- Source
- IRS.gov — Understanding Your IRS Notice
What this notice is
This is your final reminder; we still don’t have a record that you filed your prior year tax returns.
Source: IRS.gov. Reproduced for reference. General information — not legal or tax advice.
What the IRS says to do
Immediately respond to the notice by: Filing your tax return with the completed Form 15103, Form 1040 Return Delinquency PDF to explain: Why you’re filing late; or That you’ve already filed. Why you’re filing late; or That you’ve already filed. Completing Form 15103, Form 1040 Return Delinquency PDF to explain: Why you don't have to file. Why you don't have to file. Return the completed Form 15103 and tax return, if applicable to the address on your notice. You can fax it to the number in the notice using either a fax machine or online fax service. Protect yourself when sending digital data by understanding the fax service’s privacy and security policies. If you’re only sending a completed Form 15103 to explain why you don’t have to file, you can submit it online. An IRS Online Account (OLA) is required.
This is the IRS’s own guidance reproduced from the IRS notice page. It describes the IRS’s process — it is not legal or tax advice from TaxRiskOS.
Governing IRS procedure (Internal Revenue Manual)
The IRS’s own internal procedures for handling this notice type are documented in the Internal Revenue Manual:
- IRM 5.1.11 — 5.1.11 Delinquent Return Investigations
- IRM 5.18.1 — 5.18.1 Automated Substitute for Return (ASFR) Program
- IRM 4.12.1 — 4.12.1 Nonfiled Returns
Reference to published IRS procedure. General information — not legal or tax advice.
Official IRS reference
Read the official notice page on IRS.gov: https://www.irs.gov/individuals/understanding-your-cp518-notice
Related tools
TaxRiskOS is workflow software for practitioners — it captures the notice, computes the deadline, surfaces the escalation tier, and builds a document checklist. It documents process; it does not give advice or draft responses.
Check this notice’s deadline (free tool)