First of all such remote point of pumping systems should only be used for washing dishes, showering, and flushing the toilet. There are, after all, the majority of all RV useage. Drinking water is usually via bottled water or potable hook up. This includes coffee preparation.
The system begins with a series of hoses, several filter canisters, and a portable pump. Although we are not talking purely potable water, non-white hoses can be used, but I still prefer the white ones. At the point of pumping the first hose uses a drogue filter attachment entering the stream that reduces the debris often encountered. I also cover the drogue with a microfiber bag for further filtering. The point here is to place/mount the hose/drogue in a stream where it will remain suspended on a short lead while not allowing the drogue to touch or stir up the bottom.
Up hose the first filter is placed. This is determined by the distance from stream to RV. Try to avoid distances longer than 50 feet or 15 feet of elevation. I use a series of 3 Culligan RFV-10 T-Filter canisters. These accept the universally adaptable canister type filters. The beauty of these is that they are relatively cheap and can be replaced when needed. Each of these 3 filters increases the amount of filtering desired for reasonably safe water. All are connected by several feet of hose.
Filter #1: Culligan S-1 20 micron sediment filtering
Filter #2: Culligan CW-F 10 micron further sediment and purification filtering
Filter #3: Culligan D-10 5 micron final filtering w/Sodium Dichlor
The last filter (#3) is also preloaded with 1/4 teaspoon of granulated Sodium Dichlor. I add this prior to loading the canister filter and sealing. It will last one 40 gallon pump cycle. Sodium Dichlor is the basic chemical used to sterilize hot tubs and spas. It will provide enough pressurized chlorination to sterilize the water and yet is safe for human use. I chose this alternative over a basic chlorine bleach mixture. Additionally I use the mixture seasonally whenever I sterilize the fresh water tank, after winterization, or just to 'reset' the tank.
NOTE: There are always finer filters that provide filtering down to .5 microns and also claim to elimninate Cryptosporidium and Giardia. You need to know that with each level of filtering the line pressure will decrease resulting in longer tank fill times. I believe that I have found the most reasonable combination.
Of course the entire system depends on a means to transfer the water from the remote source to the RV. I chose the Wayne 1/2 HP Transfer Pump. It runs off the Honda generator and provides pumping at 50 psi. It provides effective pumping up to 15 feet elevation from the source. This will fill our 40 gallon fresh water tank in about 10 minutes.
The last measure of purfication I use is to measure the purity of my water at the tap via a water purification tester. Many different products are available. I look for my water to be no more than 300 ppm. I have never exceeded 185 ppm. with our remote pumping system. You should always check your tap water even when hooked up to a potable source. You would be surprised at water purity sometimes.
Water use can also be further conserved by saving a gallon or two of your grey water drainage in storage jugs. These can be used to manually flush the toilet w/o the pump. You would be surprised that you use about a gallon a day for flushing. I use a couple of old plastic ice tea jugs PROPERLY LABELED for this.
Also, never underestimate the power of a good rain shower. Rainwater is a very pure form of water. I have 6 small plastic buckets I place out in random locations away from trees when a good rain shower is anticipated. You can collect up to 2 gallons of water with this simple method. I prefer rain showers as a downpour will not only splash water out of the bucket, but often splashes debris into the buckets as well.