8 Deductions That Shrink a California Retiree’s First Social Security Check

More than 5.3 million Californians collect a Social Security retirement benefit, according to the Social Security Administration’s state count.

California never taxes a dollar of it.

These are the deductions that shrink a California retiree’s first Social Security check.

Note: This is general information, not financial, tax, or Medicare advice. Withholding rules, premiums, and dollar amounts are subject to change.

1. Your Medicare Part B Premium

The Social Security Administration withholds your Medicare Part B premium before your check is ever deposited.

Nearly every one of the Californians in the agency’s December count has this premium taken out first.

The standard Part B premium runs $202.90 a month in 2026, up $17.90 from the year before.

First checks are no exception.

Medicare enrollment processing sometimes runs behind schedule.

When it does, more than one month’s premium can come out of the same check at once.

The withholding simply catches up to whatever date the Part B coverage started.

2. An IRMAA Surcharge

Medicare adds an income-related monthly adjustment amount (IRMAA) on top of the standard Part B premium for retirees whose income runs higher.

The surcharge kicks in once 2024 income crossed set thresholds, since Medicare looks back two years to set the current year’s premium.

Cross $109,000 as a single filer or $218,000 filing jointly.

2026’s Part B premium then jumps to $284.10 a month.

Go past $500,000 single or $750,000 joint.

That premium reaches $689.90 at the top bracket.

Not a rounding error.

The Social Security Administration (SSA) checks that income figure automatically against your tax return.

Nobody applies for the surcharge, and nobody even knows it’s coming until the first check lands short.

3. A Part D Surcharge

Social Security collects a separate surcharge from retirees enrolled in Medicare Part D, the prescription drug benefit.

It comes out of the check no matter how you pay your plan’s base premium, a rule the agency states outright.

The add-on ranges from $14.50 to $91 a month in 2026, tied to the same income brackets as the Part B surcharge.

Both hit the same check.

A retiree who never noticed the Part B surcharge on that first check can still get caught by the Part D surcharge.

Medicare reviews Part D separately, even though it uses the same income brackets.

4. A Late-Enrollment Penalty

The check takes a permanent hit as well when a retiree delayed signing up for Medicare Part B past their enrollment window.

Medicare adds 10% to the Part B premium for every full 12-month period someone was eligible but didn’t enroll.

That surcharge usually lasts a lifetime.

Waiting three years past eligibility makes the premium run 30% higher for as long as the retiree keeps Part B.

That penalty never goes away.

It rides inside the same withholding as the standard premium, so it shrinks the first check right alongside everything else Medicare bills for.

5. Your Withholding Election

Social Security doesn’t automatically withhold federal income tax, the way an employer paycheck does.

Retirees who want tax held back have to say so themselves, filing IRS Form W-4V with the Social Security Administration and picking a rate.

The choices are 7%, 10%, 12%, or 22% of the monthly benefit.

Nothing else is offered.

File it before that first payment goes out, and the withholding already shrinks the very first check.

Skip it, and the retiree owes the whole year’s tax at once every April, sometimes with a penalty riding along.

6. An IRS Tax Levy

The IRS can pull 15% straight out of a retiree’s Social Security check automatically when federal taxes go unpaid.

The Federal Payment Levy Program pulls that share straight out of the benefit, with no separate application and no warning check first.

Many other offsets against Social Security stop at $750 in protected income.

The IRS skips that protection.

That makes a tax debt one of the few things that can shrink a first Social Security check to nearly nothing, month after month, until the balance clears.

7. A Child Support Order

A family court can reach that same check too, when a retiree owes child support or alimony from an order that predates retirement.

Federal law lets a court garnish up to 50% of the benefit, or 60% if the retiree isn’t supporting another spouse or child.

Old arrears push that ceiling to 55% or 65%, once the unpaid support runs more than 12 weeks behind.

It happens every month.

That includes the very first check a new retiree ever sees, since the order doesn’t care when Social Security starts paying.

8. A Prior Overpayment

SSA can start that first check smaller than expected when a retiree already owes money from an earlier benefit period.

SSA's default policy withholds 50% of the monthly benefit to recover an old overpayment, a rate that's been in place since April 2025.

That default applies automatically unless the retiree requests a lower rate or files a waiver first.

Half of it never arrives.