Before you start

An SSN or ITIN
Form W-4 with your employer for federal withholding
Your municipality and school district, and their PSD code, for local withholding
Records of foreign income and foreign financial accounts

Step-by-step

1
Complete the federal W-4 and give payroll your PSD code on day one
Pennsylvania's flat rate needs no allowances, but your local earned income tax does need the Political Subdivision code for the municipality and school district you live in. Get it from the state's local income tax register using the exact address; guessing means money withheld for the wrong government.
Via employerWho: YouFirst week of employment
2
Understand that the flat rate has no floor
Pennsylvania taxes at 3.07% with no standard deduction and no personal exemption for most filers, so nearly all earned income is in the base. Someone comparing a Pittsburgh offer to a graduated-tax state should model the actual take-home rather than compare headline percentages. Low-income filers should check Schedule SP — the Tax Forgiveness credit — which is the one significant relief.
OnlineWho: You
3
Add the local layer to any salary comparison
A City of Pittsburgh resident pays 3% local earned income tax on top of the state's 3.07%, split 1% to the city and 2% to the school district. It follows residence, not workplace. A neighbouring borough may charge a different total, so the same salary nets differently across a street. Look the address up before signing a lease, not after.
OnlineWho: You
4
Expect the $52 Local Services Tax if you work in the city
The Local Services Tax is levied on the privilege of working within Pittsburgh, at $52 a year, typically withheld pro rata across pay periods. It applies whether or not you live in the city, and there is a low-income exemption you must claim rather than receive automatically.
Via employerWho: You
5
Determine your US tax residency
The substantial presence test counts weighted days across three years to decide whether the US taxes your worldwide income or only US-source income. Your visa category does not decide this.
OnlineWho: You
6
Check for an applicable tax treaty
The US has treaties with around 70 countries that can reduce or exempt tax on particular income. Pennsylvania's return does not start from federal taxable income the way most states' do — it taxes eight discrete classes of income on its own rules — so a federal treaty position does not automatically flow through. Check the state treatment separately rather than assuming.
OnlineWho: You
7
File federal, Pennsylvania and local returns
The tax year is the calendar year and the federal deadline is normally 15 April. Pennsylvania has its own return, and — unlike Maryland, where the local tax rides on the state return — your local earned income tax is a SEPARATE annual filing with the regional tax collector for your area. Three returns, not two.
OnlineWho: YouBy 15 April annually
8
If you buy, look at the assessment and the homestead exclusion
Allegheny County assesses against a 2012 base year and reconciles current values through the Common Level Ratio, so the number on your bill is not the price you paid. Apply for the Act 50 homestead exclusion, which takes $18,000 off the county-assessed value of an owner-occupied home but only for owners with the application on file.
OnlineWho: You
9
File an FBAR if foreign accounts exceed $10,000
Aggregate foreign account balances over $10,000 at any point in the year trigger a FinCEN filing, separate from your tax return and with its own penalties.
OnlineWho: You

Documents you’ll need

Form W-2 from each employer, issued by 31 January
Form 1099s for freelance, interest and investment income
Your PSD code and local tax collector details
Passport and travel history for the substantial presence day count
Foreign account statements for FBAR reporting

Things most newcomers don’t know

A flat 3.07% with no standard deduction is not the same as a low tax.

Most US states with graduated rates give a substantial untaxed band at the bottom. Pennsylvania gives most filers none at all, so the flat rate bites from close to the first dollar. On a modest income the effective rate here can exceed a state whose top bracket is far higher. Model the take-home, do not compare headlines.

Source: Pennsylvania Department of Revenue

Two separate governments levy your local wage tax, and the school district takes the larger share.

A City of Pittsburgh resident's 3% local earned income tax is 1% to the city and 2% to the Pittsburgh School District — the district, not the city, is the bigger claimant. It follows residence, so moving across the city line into Mt Lebanon or Wilkinsburg changes both components. It is the single most useful thing to check about an address.

Source: City of Pittsburgh — taxes

The Local Services Tax follows your job, not your home.

Pittsburgh's $52 Local Services Tax is charged for the privilege of working in the city, so commuters from the boroughs pay it too, while a city resident working elsewhere pays that municipality's version instead. It is small, it is easy to be double-withheld on if you have two jobs, and the refund is yours to claim.

Source: City of Pittsburgh — taxes

Your local earned income tax is a third return, not a line on the state one.

Pennsylvania's local tax is administered regionally by appointed collectors, not by the Department of Revenue, so it needs its own annual filing even when it has been fully withheld. Newcomers from single-return states miss it, and the collector eventually writes to them.

Source: Pennsylvania Department of Community and Economic Development

Your visa does not determine your tax residency.

The substantial presence test — a weighted day count across three years — decides whether the US taxes your worldwide income. Someone on a temporary visa can be a US tax resident; someone on a long visa can fail the test. Do the count rather than assuming.

Source: IRS — substantial presence test

Common mistakes to avoid

Comparing a flat 3.07% to another state's headline rate without noticing there is no standard deduction.
Giving payroll the wrong PSD code and funding the wrong municipality all year.
Forgetting the separate local earned income tax return because it was all withheld.
Being double-withheld for the $52 Local Services Tax across two jobs and never claiming it back.
Buying a house without checking the parcel's 2012-base assessment and the appeal calendar.
Missing the FBAR because a home-country account did not feel 'foreign'.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.