If you use a 12 Volt RV style pump for your water, you need to install one of these RIGHT NOW!
It’s called an Accumulator tank, and it is much like the bladder tank you’ll find in a typical residential water system that is fed from a well. It’s purpose it to maintain pressure in the system, and it provides a number of wonderful benefits.
I have described my water system before, in case you want to get up to speed. I use a demand water system. The pump has a pressure switch that turns on when the water pressure drops. So basically, when I turn on the faucet, the pressure drops causing the pump to turn on and supply water. When I turn the faucet off, the pressure quickly builds back up, and the pump turns off. Thats simple on paper, but in practice it has some drawbacks. Chiefly, you cannot turn the water on a little. The faucet has to be wide open, if at all. Otherwise, the pump suffers from pulsation. It’s reminiscent of “water hammer”, but its different. When the water flow is restricted by a semi-open faucet, the pump turns on and off rapidly as the pressure rises and falls over and over again. It’s annoying, and its bad for the pump. It also makes using a sprayer difficult. My sprayer caused pulsation until I modified the mesh outlet. With this tank, that would not have been necessary. Having to run the water wide open means a lot of water gets wasted while rinsing dishes or washing hands. Not to mention the mess of water around the sink that results from the impetuous flow.
Enter the accumulator. It is a 
pressure vessel that contains a bladder that is filled with air to 30 PSI. When water is pumped in, it compresses that bladder, increasing the pressure to a point that tells the pump to turn off. When I open the faucet, the initial water pressure comes from the ACCUMULATOR, not the pump. This means that I can turn the faucet on as little or as much as I need to. As the water leaves the accumulator, the pressure eventually drops until the pump turns on to maintain the flow of water. When the faucet is turned off, the pump will continue to run, filling the accumulator until the bladder provides enough pressure to turn the pump off. It’s a lot like a capacitor, but it stores hydraulic energy as opposed to electrical. And, much like a capacitor will filter or “smooth” out a signal, this smooths out the water flow. It took a moment to get used to, as the pump does not turn on right away with the faucet, and it runs for a few seconds after you turn it off.
It comes pre-charged to 30 PSI. It has a standard air valve, should you need more pressure for your particular pump, or if you need to replenish pressure lost over time. It came with a coupler, so installing it right next to the pump required no additional fittings or hardware. They are commonly available for $40-50. In my humble opinion, this is a must have item. I wish I had done this sooner.