Chapter 40: 7-9
The Laws of Washing Before a Meal7. A person who does not have a proper vessel for washing hands may immerse his hands in a river, a mikvah fit for the immersion of women (see Chapter 162 for particulars regarding the use of rivers for this purpose), or a spring, even if it contains less than 40 seah.* Under extreme circumstances one may also immerse one's hands in snow, if there is enough on the ground to complete the measure of a mikvah.
* {Forty seah is the minimum amount of water necessary for a kosher mikvah. A spring (and similarly, a river when fit for immersion) need not contain this quantity of water to be kosher for immersion. However, the Shulchon Oruch HoRav 159:21 and the Mishnoh B'rurah 159:82 mention a diversity of opinion among the Rabbis whether a mikvah must contain this quantity of water to be used for the immersion of one's hands or not.}
A person who must wash his hands from a pump should place one hand close to the ground* and pump the water with his other hand, and then switch hands. Alternatively, a colleague should pump for him. However, if his hands are lifted above the ground, the washing is invalid.
* {This applies to a pump which does not have a receptacle. Hence, when the person's hands are on the ground it is considered as if he is immersing them in the well from which the water is drawn (Mishnoh B'rurah 159:47, Sha'arei Tziyun 45).}
8. Water whose color has changed, either because of the place where it is contained or because something has fallen into it,* may not be used to wash one's hands. However, if the color change is due to natural causes, the water may be used.
{* If the color of the water changes because dirt or mud fell into it, it may be used for washing, provided it is fit for a dog to drink from (Shulchon Oruch HoRav 160:1, Mishnoh B'rurah 160:3).}
Water that was used for work - e.g., to wash dishes, soak vegetables, or to cool containers of liquid placed in them - is also unfit for this purpose. Some also forbid the use of water that has become disgusting - e.g., if a pig, dog, or the like drank from it. This causes it to be considered as sewage. This opinion should be taken into consideration.
9. The fact that a person who had not washed his hands touches water does not make it impure and disqualify it for use. Therefore, a person who leaves the lavatory can scoop water out of a barrel with his hands in order to wash them and the water remaining is still fit to be used for the washing of hands. However, if he rubbed his hands together in the water to clean them - or even dipped his pinky into the water to clean it - all the remaining water is unfit for washing because work has been performed with it.
