1099 Contractor in Washington with a Colorado Client: Where Do You File?
Answer
The client's address is not the test. Washington has no personal income tax, so nothing is owed at home; Colorado taxes nonresidents on income from services performed within Colorado, so if you never travel there to work, there is nothing to file. Days on site change that.
Last verified
The most common contractor worry — that invoicing an out-of-state client creates a filing obligation there — is usually unfounded. What creates the obligation is physical presence, and Washington residents have no home-state return in any case.
Colorado publishes no de minimis day count or dollar floor for nonresidents. Any Colorado-source wage income above the state's general filing threshold requires a nonresident return, and that threshold is reset each year — check the current figure on the Colorado Department of Revenue — Taxation Division nonresident instructions before filing.
What you file
- 1Nonresident return · ColoradoForm DR 0104 with Schedule DR 0104PN
File a Colorado nonresident return only for income from services you physically performed in Colorado. Washington does not tax wage or self-employment income.
The two states, side by side
| Washington | Colorado | |
|---|---|---|
| Taxes wages | No | Yes — flat |
| Reciprocity partners | None | None |
| Convenience rule | No | No |
| Nonresident return | Not applicable | Form DR 0104 with Schedule DR 0104PN |
| Credit for other-state tax | No income tax | Form DR 0104CR |
| Nonresident safe harbour | Not applicable | None published |
| Local income tax | No | Yes |
| Revenue department | Washington State Department of Revenue | Colorado Department of Revenue — Taxation Division |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Colorado and working in Washington gives:Home state only — estimated payments.
Same two states, different situation
The withholding answer turns on how you are paid and where the work happens, not only on which two states are involved.
- W-2 commuter: Washington → ColoradoWork state only
- Remote worker: Washington → ColoradoNo state income tax on your wages
- Moved mid-year: Washington → ColoradoOne part-year return — the state you moved to
Other Washington pairs
Questions people actually ask
I live in Washington and my client is in Colorado. Do I have to file a Colorado tax return?
The client's address is not the test. Washington has no personal income tax, so nothing is owed at home; Colorado taxes nonresidents on income from services performed within Colorado, so if you never travel there to work, there is nothing to file. Days on site change that.
Do reciprocity agreements help a 1099 contractor?
No. Every state reciprocity agreement in the country is an arrangement about wage withholding between two revenue departments, and a 1099 has no withholding to switch off. Whether Washington and Colorado hold an agreement makes no difference to a self-employed filer — sourcing rules decide the answer instead.
How current is this?
The Washington and Colorado rules on this page were last checked against Washington State Department of Revenue and Colorado Department of Revenue — Taxation Division on 2026-08-07. We re-check the full grid every December after state legislative sessions close, and re-check the convenience-of-the-employer states quarterly because that is where the rules move fastest.
Sources
Every fact above comes from the revenue department that publishes the rule. We do not cite secondary summaries, and we do not restate a figure we could not find at source.
- Washington State Department of Revenue — individual income taxaccessed 2026-08-07
- Colorado Department of Revenue — Taxation Division — individual income taxaccessed 2026-08-07