The figure below shows the two main families of acetylcholine receptors: muscarinic and nicotinic. In structural terms, muscarinic receptors are G-coupled protein receptors, while nicotinic receptors are ligand-gated ion channels. They can be found on both sides of the synaptic cleft (presynaptic and postsynaptic).
After the pressure drops below 40 psi, the electrical switch turns on the pump and the pressure in the tank increases. Any failure in any component or loss of electricity can cause a well to suddenly stop producing water when a faucet is turned on.
Boil Water Response - Information for the Public Health Professional. Boil Water Orders and Notices are often used by health agencies and drinking water utilities in response to conditions that create a potential for biological contamination in drinking water. Common reasons for a boil water response include loss of pressure in the distribution system, loss of disinfection and other unexpected water quality problems. Often these result from other events such as water line breaks, treatment disruptions, power outages, floods and other severe weather.