I am eligible for a PhD studentship stipend

Do most universities impose the three years resident condition to those applying for PhD studentships with yearly stipends? I have seen a few studentship positions that state you need to be a UK citizen or an ordinary resident for three years, but many don't specify.

Has anyone on here been able to obtain a studentship with a stipend without these conditions?

From what I've heard, you do usually have to be a UK/EU resident or citizen in order to qualify for the stipend. At least, this was the case for Bristol University, where I did my masters. The department told us that anyone applying for a PhD from outside the EU would be responsible for funding themselves or finding their own sponsor. In fact, even some of the UK/EU students may have had to do this too as last year they had over 100 PhD applicants and only 6 stipends available!

Is that for science related PhDs? I thought studentships in science were always paid?

Yes, it was in an Earth Sciences department. The funding was coming from research councils such as NERC, so I'm wondering if maybe they have restrictions on the people they agree to fund in terms of residency.

It doesn't really seem fair because as a UK citizen, I had no trouble getting a TA assistantship and tuition paid for a US university - I am now a PhD student in Geophysics in the US.

Interesting.

Well, I had been toying with the idea of doing one with the IAH, since it's close to where I will be moving, and already know people who are employed at the Compton branch. I seems that most studentships there are funded by BBRSC which one would have to meet the residency requirement in order to qualify, however there are a few that are funded by the IAH, which simply states are open to all "suitably qualified students". I take that as meaning one doesn't have to meet residency requirements.

So I guess it all depends on the funding source.
Thanks for your help, and good luck with your PhD. I have an aunt who does something with geophysics in Illinois.

Yes, it was in an Earth Sciences department. The funding was coming from research councils such as NERC, so I'm wondering if maybe they have restrictions on the people they agree to fund in terms of residency.

It doesn't really seem fair because as a UK citizen, I had no trouble getting a TA assistantship and tuition paid for a US university - I am now a PhD student in Geophysics in the US.

Yes, NERC funding is only available to UK residents (3 year residents).  It's easier in the US because the residency requirements aren't so harsh (usually only 1 year).