Tax · United States
IRS Notice CP503 — the second reminder about an unpaid balance
A CP503 means the IRS has not heard from you and a balance is still unpaid on a tax account. It is a routine reminder — but it precedes the levy-threat notices, so it marks the point where the sequence starts to escalate.
How serious: needs actionAlso called: CP503, second reminder notice, IRS urgent reminder
The CP503 is a reminder in the IRS collection sequence. It is sent because the IRS has not heard from you and its records still show an unpaid balance on one of your tax accounts.
The notice repeats the amount due and warns that a federal tax lien can be filed. The wording sounds urgent — 'Immediate action is required' — but it is still a reminder, not a seizure.
It sits just before the levy-threat notices in the sequence. If the balance stays unresolved, the next letters carry intent-to-levy language.
Who sends it
The Internal Revenue Service (IRS) — the United States federal tax authority, part of the Department of the Treasury.
The code 'CP503' is printed in the top corner. The language runs along the lines of 'Second reminder — you have an unpaid balance' or 'Immediate action is required'. The notice shows the amount owed, a due date, payment options and a toll-free number, and includes a payment envelope.
The deadline
Pay the entire balance by the due date shown on the notice ('You must pay the entire balance by the due date shown on your notice to avoid additional penalties and interest')
The notice states that the entire balance must be paid by the due date shown on it to avoid additional penalties and interest; the date is counted from the date printed on the notice.
If you do nothing
The IRS may file a Notice of Federal Tax Lien — a public notice to your creditors that the IRS has a right to your interests in your current assets and any assets acquired after the lien is filed; it can affect the ability to get credit. Interest and penalties continue, and if the balance stays unpaid the IRS can issue a CP504 Notice of Intent to Levy.
How it escalates
- 01A Notice of Federal Tax Lien may be filed, which can harm access to credit.
- 02If payment is still not received, the IRS issues a CP504 'Notice of Intent to Levy'; if the amount due is not received within 30 days of that notice, the IRS can levy a state tax refund.
- 03A final notice with Collection Due Process hearing rights (LT11 / Letter 1058 / CP90) follows; 30 days later the IRS can levy wages, bank accounts, Social Security benefits and other property.
Common questions
Is money being seized at the CP503 stage?
No. The CP503 is a reminder. Levy of a state tax refund becomes possible only 30 days after a later notice, the CP504 — and levy of wages or bank accounts requires a further final notice with hearing rights.
Why does the notice sound so urgent?
The CP503 uses wording like 'Immediate action is required' and precedes the levy-threat notices. It is still a reminder that the balance remains unpaid — nothing is taken by this letter itself.
What does the lien warning mean?
A tax lien is a public notice to creditors that the IRS has a right to your interests in your current assets and assets acquired after the lien is filed. It can affect the ability to get credit.
Sources
Facts verified against the sources below on 28 August 2026.