I checked the pregnancy test sticky and while your question isn't addressed specifically, a couple of notations imply that if you drink too many fluids before testing, your urine could be too diluted.
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15. Do I have to test with my first morning urine (FMU)? Not necessarily. In general, FMU is the most concentrated urine of the day and thus more likely to have built up more hCG in it. If you are testing early (before 14 DPO), the HPT is more likely to detect the hCG in your FMU. After 14 DPO there should be enough hCG to be detected at any time of day. Some women have better luck with second morning urine (SMU.)
A good rule of thumb: hold your pee for 3-4 hours (and drink as little as possible!) Then pee in a cup. If your urine looks nice and yellow, it's concentrated enough for testing (see FAQ 16 below for more info on peeing in cups vs. peeing on sticks.) If it looks diluted, dump it and try again later.
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Tips For Getting Accurate ResultsBe sure to read the test instructions carefully, taking special notice of the test reading time. Most home pregnancy tests will tell you not to read your test after a certain amount of time. If a line appears after this time period, it should not be counted as a positive pregnancy test. What you may see is an evaporation line, usually colorless, but slightly darker than the color of the pregnancy test membrane. Evaporation lines can occur as your urine dries on the test.
Using first morning urine is a good way to make sure the HCG in your urine is concentrated, making it easier for the pregnancy test to return a positive result if you are pregnant.
If you want to test in the middle of the day,
you will want to limit fluid intake for several hours to make sure your urine is not diluted. 
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