Here are more of the details from Medscape:

"Of 11 included trials, 7 compared rates of infection and healing in wounds cleansed with water vs normal saline, 3 trials compared cleansing vs no cleansing, and 1 trial compared procaine spirit vs water. Procaine spirit is a mixture of procaine HCl 2% with spirit 70% and is commonly prescribed for wound cleansing following surgery. Ability to pool the data was limited because there were no standard criteria across the trials for evaluating wound infection. The predominant comparisons were water vs normal saline and tap water vs no cleansing.

When chronic wounds were cleansed with tap water vs normal saline, the relative risk (RR) of developing an infection was 0.16 (95% confidence interval [CI], 0.01 - 2.96). Compared with saline, tap water was more effective in reducing the infection rate in adults with acute wounds (RR, 0.63; 95% CI, 0.40 - 0.99). In children, the use of tap water to cleanse acute wounds was not associated with a statistically significant difference in infection vs saline (RR, 1.07; 95% CI, 0.43 - 2.64).

When wounds were cleansed with tap water or not cleansed at all, there was no statistically significant difference in infection rates (RR, 1.06; 95% CI, 0.07 - 16.50). In a similar fashion, episiotomy wounds cleansed with water or with procaine spirit did not differ in infection rate. For cleansing open fractures, use of isotonic saline, distilled water, and boiled water was not statistically significantly different in the number of fractures that became infected.

"There is no evidence that using tap water to cleanse acute wounds in adults increases infection and some evidence that it reduces it," the review authors write. "However there is not strong evidence that cleansing wounds per se increases healing or reduces infection. In the absence of potable tap water, boiled and cooled water as well as distilled water can be used as wound cleansing agents. . . . The decision to use tap water to cleanse wounds should take into account the quality of water, nature of wounds and the patient's general condition, including the presence of comorbid conditions."

Keep in mind these are limited studies and it is often difficult to compare field received wounds, which by their very nature will vary in degrees of possible contamination.

I think the take home message is not to take things to an extreme, if all you have is drinkable water (vs. sterile saline) that should suffice for most incidences.

Pete