Colourless urine indicates a dilute urine where lots of water is being excreted. If you're drinking a lot of fluid urine can be white in colour .Also colorless urine may be caused by conditions such as long-term kidney disease or uncontrolled diabetes.
Ideally a Urine routine examination ,RFT and blood sugar levels may be further evaluated .You may consult your doctor for a clinical examination .
Hope this helps
Well as such colourless urine can be due to excessive intake of water but i agree that if you are not taking enough fluids it may not be the case with you .
Ideally a renal function test to evaluate the functioning of the kidney ,Urine examination , blood sugar levels may be considered in your case .
Check this link from a website wrong diagnosis to read about the possible causes of clear urine .