I suggest you consult a local tax professional.
Your situation is potentially one of dual residency. You are a domiciliary resident of MD, because that is the location of your permanent home. If you rent an apartment in DC as you plan, you may additionally become a statutory resident of DC. Here is DC's rule: "Section 47-1801.04(17) of the DC Official Code describes a statutory resident as any individual who maintains a place of abode within the District for an aggregate of 183 days or more during the taxable year, whether or not such individual is domiciled in the District."
Both DC and MD tax residents on ALL their income.
Since DC and MD have tax reciprocity, it is possible that neither will give an out-of-state credit for taxes paid to the other. Thus you may face dual taxation.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
