Very Small Water System Operator key terms

A treatment step in which a chemical is rapidly mixed into water so tiny suspended particles clump together into larger masses that can be removed by later settling and filtration.

Gentle, slow stirring of chemically treated water that encourages small particle clumps to collide and grow into larger, heavier masses called floc that settle out more easily.

A process where water sits quietly in a basin long enough for heavier suspended solids and floc to sink to the bottom and be removed as sludge.

Passing water through a bed of sand, anthracite, or other media to trap remaining particles and organisms, producing clearer water before disinfection.

Reversing the normal flow of water upward through a filter at a high rate to flush out trapped particles and restore the filter's ability to clean water.

The period a filter operates between backwashes, ending when the filter becomes clogged, turbidity breaks through, or a set head loss limit is reached.

A measure of how cloudy water is because of suspended particles; high turbidity can shield pathogens from disinfection and is a key indicator of treatment performance.

A treatment step that kills or inactivates harmful microorganisms in water, usually by adding chlorine or another disinfectant, to protect public health.

The amount of chlorine still present in water after treatment, measured as free or total chlorine, which shows the water remains protected against contamination as it travels.

A disinfection measure calculated by multiplying the disinfectant concentration (C) in milligrams per liter by the contact time (T) in minutes that water is exposed to it.

The length of time treated water stays in a storage tank or pipe while in contact with a disinfectant, needed for the disinfectant to work effectively.

The drop in water pressure as water moves through a filter or pipe because of friction or clogging; rising head loss across a filter signals it needs backwashing.

The raw water taken from a well, spring, river, or lake before any treatment; its quality determines what treatment steps a system must provide.

Water as it enters the treatment plant, before any chemical addition or physical processing, used as the baseline for judging treatment effectiveness.

Water that has completed all treatment steps and is ready to enter the distribution system or be delivered to customers.

Water drawn from beneath the earth's surface through wells or springs; it is often clearer and less contaminated than surface water but can carry minerals or contamination.

Water from rivers, lakes, reservoirs, or streams that is open to the environment and generally requires full treatment including filtration and disinfection.

The network of pipes, pumps, valves, tanks, and meters that carries finished water from the treatment plant to homes and businesses.

A large pipe in the distribution network that carries water through streets and neighborhoods to serve many service lines and fire hydrants.

The smaller pipe that connects an individual building or customer to the public water main and delivers water to the property.

The force pushing water through pipes, usually measured in pounds per square inch; adequate pressure keeps water flowing and prevents contamination from entering the system.

A loud banging or shock in pipes caused by a sudden change in flow, such as a fast-closing valve, which can damage pipes and fittings.

Any actual or potential link between the drinking water system and a source of contamination, such as a hose in a chemical bucket, that could allow backflow.

The unwanted reverse flow of water or other liquids into the drinking water system, often caused by a pressure drop that pulls contaminants in.

A mechanical device such as an air gap or check valve assembly installed to stop contaminated water from flowing backward into the drinking water supply.

A device that measures the volume of water used by a customer, used for billing and for tracking how much water a system produces and loses.

The difference between water produced or purchased and water sold or metered; a large gap can indicate leaks, meter errors, or unauthorized use.

The practice of finding hidden water losses in pipes and tanks using methods such as listening devices, metering analysis, and inspecting for wet spots or low pressure.

Deliberately running water through mains or hydrants to remove sediment, stale water, and biofilm, and to restore disinfectant residual in the pipes.

A structure that holds treated water to meet peak demand and fire flow needs and to provide contact time, but which must be managed to keep water fresh.

A device in a pipe that starts, stops, or controls water flow; valves are used to isolate sections of main for repair and to regulate pressure.

A public warning telling customers to boil tap water before drinking or cooking because the water may be contaminated, often issued after a main break or loss of pressure.

The required process of informing customers about violations or health risks in their water, including the method, timing, and wording of the notice.

The highest level of a contaminant allowed in drinking water under federal rules, set as close to the health goal as is feasible with available technology.

The level of a contaminant below which there is no known or expected health risk; it is a non-enforceable health target, not a legal limit.

The scheduled collection and testing of water samples to check that treatment is working and that contaminant levels stay within regulatory limits.

A specific location chosen for collecting water samples, such as a customer tap or entry point, so results fairly represent water quality in the system.

A written record that tracks each sample from collection through transport to the laboratory, showing who handled it and when, to keep results legally valid.

A person who has met state requirements for training, experience, and examination and holds a valid license to operate a public water system.

A system that provides water for human consumption through pipes or other conveyances to at least 25 people or 15 service connections for at least 60 days per year.