MS Water Operator key terms

The addition of a chemical such as alum or ferric chloride to water so that small suspended particles clump together and can be removed in later treatment steps.

Gentle, slow mixing that encourages the small clumps formed during chemical addition to collide and grow into larger, heavier masses that settle more easily.

A settling process in which water sits quietly in a basin long enough for heavier particles and floc to sink to the bottom and be drawn off as sludge.

Passing water through a bed of sand, anthracite, or other media to trap remaining particles and organisms that did not settle out in earlier steps.

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 effluent quality drops, head loss becomes excessive, or a set run length is reached.

A measure of how cloudy water is because of suspended particles, reported in nephelometric turbidity units and used as a key indicator of treatment performance and microbial risk.

Killing or inactivating disease-causing organisms in water, usually with chlorine, chloramine, ozone, chlorine dioxide, or ultraviolet light, to prevent waterborne illness.

The product of disinfectant concentration in milligrams per liter and contact time in minutes, used to confirm that enough disinfection has been delivered to inactivate pathogens.

The amount of chlorine still present in water after treatment and as it travels through pipes, which keeps protecting against contamination and is measured in the field.

The drop in water pressure as water moves through a filter bed or piping because of friction and clogging, often used as a signal that a filter needs cleaning.

Water as it arrives at a treatment plant from a river, lake, or well, before any treatment has been applied and before it is safe for drinking.

Water that has completed all treatment steps and is ready to leave the plant and enter the distribution system, having met required quality standards.

The river, lake, reservoir, spring, or aquifer from which a public water system draws its supply, which must be protected from contamination.

An underground layer of sand, gravel, or rock that holds and transmits enough groundwater to supply a well or spring.

Water stored in the spaces and cracks of underground soil and rock, typically lower in turbidity and microbial content than surface water but often high in dissolved minerals.

Water found in rivers, streams, lakes, and reservoirs, which is exposed to runoff and weather and therefore needs more treatment than most groundwater.

A program that identifies the land area contributing water to a well and manages activities there to prevent contaminants from reaching the supply.

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

Any actual or potential link between the drinking water supply and a source of contamination or nonpotable water that could allow backflow into the pipes.

Devices and practices such as air gaps, reduced-pressure-zone assemblies, and vacuum breakers that stop water from flowing backward from a customer's plumbing into the public supply.

A pipe section with no outlet that allows water to stagnate, lose disinfectant residual, and accumulate sediment, requiring flushing or looping to correct.

A planned method of opening hydrants in sequence while closing valves so water travels one direction at high speed through mains, scouring out sediment and stale water.

A valved connection on a water main used by fire crews for suppression and by utility staff for flushing, flow testing, and pressure monitoring.

A pressure surge caused by a sudden change in flow velocity, such as rapid valve closure, that can crack pipes and damage fittings.

A vessel or standpipe connected to a pipeline that absorbs sudden pressure changes and keeps flow more steady, protecting pipes from water hammer.

The highest concentration of a regulated contaminant allowed in water delivered to the public, set as close to the health goal as is technically and economically feasible.

The level of a contaminant below which no known or expected health risk exists, used as a health target rather than an enforceable limit.

A regulation that sets an enforceable limit or treatment technique for a contaminant that poses a health risk, such as nitrate, lead, or pathogens.

A non-enforceable guideline for contaminants that affect taste, odor, color, or appearance rather than health, such as iron, manganese, or sulfate.

An annual notice that community water systems must deliver to customers, summarizing the source of the water, detected contaminants, and compliance with standards.

A system that provides piped water for human consumption to at least 15 service connections or 25 people for at least 60 days a year, and is therefore regulated.

A public advisory telling customers to boil tap water or use bottled water because contamination or loss of treatment pressure may have made the water unsafe.

A space large enough to enter, with limited entry and exit, not designed for continuous occupancy, such as a vault or wet well, requiring a permit and atmospheric testing.

A procedure for shutting off and physically locking energy sources, then tagging them, so equipment cannot be started while someone is working on it.

A toxic, flammable gas with a rotten-egg odor that forms in sewers and tanks; it can deaden the sense of smell, so it must be detected with instruments before entry.

Gear such as gloves, goggles, respirators, and boots worn to shield a worker from chemical, biological, and physical hazards on the job.

A document supplied by a chemical manufacturer that lists hazards, safe handling steps, first aid, and spill response for a product stored or used at the facility.

A written record tracking each sample from collection through laboratory analysis, showing who handled it, when, and for what purpose so results hold up as valid.

A sample made by combining portions collected at several times or locations, which gives an average picture of water quality rather than a single moment.

A single portion of water collected at one time and place, used when an instant reading is needed, such as for chlorine residual or bacteria testing.