I'm on felony dwi probation. Took drug and alcohol urine test last month, they said I failed for alcohol. I 100% didn't drink! Now I'm probably going to be revoked and go to jail. What can I do about this? There is no way I should have failed it. How accurate a

Depends on test. If the test they did was a urine ethyl glucuronide (etg) or ethyl sulfide (es), the federal government (samhsa) has said this particular test is too sensitive to things like breathing in the fumes of skin sanitizers like purell or alcohol in mouthwashes. They state that it should not be used for forensic (legal) purposes. If you don't have a lawyer, get one.
Blood . Blood alcohol concentration (bac) is the most accurate way to determine alcohol levels. My understanding is that when alcohol is measured through urine it is more to determine the presence or absence of alcohol rather than an exact level. Most laboratories have to adhere to rigorous standards with both internal and external monitoring to be certified. Reportedly sugar or acetone in urine have the potential to effect a urine alcohol screen. If you think that this that there was a false positive on your alcohol screen, i suggest you obtain legal advice.