Water, water everywhere and each drop is likely to contain:

Chlorine to disinfect the water, fluoride to prevent tooth decay, lime to retard corrosion in water pipes and other chemicals such as aluminum sulfate, carbon, potassium permanganate, copper sulfate, sulfur dioxide, sodium bisulfite and ammonia.

Arsenic, lead, mercury, iron, copper, chromium, barium, silver and other metals that give water its distinctive taste.

Nitrites, nitrates and other inorganic compounds that the water collects from rainfall and from the ground.

Trihalomethanes, a suspected cancer-causing organic material formed in the water when chlorine additives interact with material already in the water such as dead vegetation.

Bacteria. "You can't kill all bacteria in water -- it isn't possible," said James Warfield, a representative of the Fairfax County Water Authority, which operates the Occoquan Reservoir.

In all, 60 chemicals are used by U.S. plants as additives in the collection, treatment or delivery of drinking water. Individual plants, however, may add less than a dozen chemicals to their water.

Despite all this, the materials in Washington's drinking water -- bacteria, organic material, inorganic compounds, metals and chemicals -- are within the tolerances allowed by government standards, according to water system officials in the federal and local governments.

Does that mean Washington's water is safe?

"Yes, definitely safe," said Bernard Sarnoski, chief of the u.S. Environmental Protection Agency's drinking water section for the Washington region.

However, activists who have fought for expanded government monitoring and regulating of chemicals that have been found in water in some parts of the country aren't as quick to declare our water safe.

"Safe?That is a relative word," said James T.B. Tripp of the Environmental Defense Fund Inc., a politically active group. "Water can meet all [existing] standards for drinking water but still be contaminated. Regulations do not adequately address that problem and God knows if they ever will."

Safety questions aside, water -- the basic and most vital consumer item purchased and used by all -- leaves many consumers dissatisfied.

"Occasionally, when I am in the shower, I feel like I am being gassed -- I am sure it is the chlorine that produces this effect . . . but it is overpowering," said Charles Peters, a District of Columbia water customer who is the editor of the Washington Monthly.

Some also complain of foul tastes from the chlorine and suspicious rings around the water bowls left out for their pets. Others say their tropical fish have died from chemicals in the water. And a few in the Fairfax City area, which has been plagued by below-normal levels of water in its main creek supply, wonder if they should drink the "nauseous-smelling" water they sometimes get when they turn on the tap.

Regardless of quality, Washingtonians will have an adequate quantity of water for normal needs for the next 10 to 15 years, unlike other parts of the country that have suffered droughts. Plans are being made now to provide for the time when demands could exceed the supply available for the region.

Water may also be one of the best buys available.

A family of four using an average 80,000 gallons a year pays less than $1 a day to bring water into the home and to send waste out. But actual costs vary enormously, since rates are set by different jurisdictions with different philosophies and expenses.

In one survey of nine local jurisdictions, the price for that annual 80,000 gallons ranged from a low of $90.04 for water and sewer in the District of Columbia to a high of $267.47 in Fairfax City.

That gap is narrowing, however.

Starting Wednesday, the rates for District water customers will increase 35 percent. Instead of $90.04 a year, the family would pay $121.59.

Washington area residents and visitors consume an estimated 410 million gallons of water each day. Most of it comes from the Potomac River, which collects water from a 12,000-square mile watershed. The Patuxent in suburban Maryland and the Occoquan in Virginia also are important sources of water.

One way that water systems traditionally have made water safe is by adding chemicals to water at the purification plants. Chlorine is the mainstay of the chemicals. Because of its odor, it also is the source of many of the complaints about the quality of Washington's water.

Harry Ways, chief of the Washington Aqueduct, said the chlorine in the water "isn't enough to gas anyone by any means, but it may well be noticed."

He said chlorine smells would be most obvious when someone turns on the hot water tap, offering a release for chlorine gases that have built up in the water heater's tank. Some customers may notice the odor more than others because they are particularly sensitive to chlorine smells or because they are close to a treatment plant, main transmission lines or chlorination stations.

Ways said that when he catches a sniff of chlorine in his water his reaction is: "Thank God it is there. Before we put it into the water, thousands of people died of typhoid fever. Chlorination wiped that out overnight."

Customer Peters also worries about the ring he has seen in his cat's water bowl. "I notice a hard black residue around the bowl and I think, 'My God, this is what I am drinking.' It is the settlement from the water and it is going inside me. It may be harmful. It may be nutritious. I don't know."

Actually, it is neither, according to Ways.

Although the ring could represent impurities that get into the water from the environment in Peter's home -- or perhaps from the cat as it drinks from the bowl -- Ways said the residue most likely is calcium carbonate (lime).

"It's what builds up in a tea kettle after repeated boiling of water," Ways said. And the lime, within allowed levels, doesn't hurt or help the person drinking the water, he said.

The Potomac River collects lime naturally as it cuts through the Shenandoah Mountains and flows down into the Cheaspeake Bay. Some lime is also added to the water at the purification plant to reduce the acidity and cut down on pipe corrosion.

At the treatment plant, water taken directly from the river's flow or from the reservoir's storage is moved through several processes. The first step typically is to force the solid particles in the water to coagulate and settle to the bottom. This gets rid of some metals and minerals, as well as mud and other suspended material in the water. After the settling, the water is filtered to remove any small particles that remain. Then chemical additives are fed into the water. The entire purification process takes about four hours, from the time the water enters the plant until it is ready to be pumped out to customers.

Chemicals added to the water at the treatment plant include:

Copper culfate, which may be sprayed onto the water in the reservoir to kill algae growth. Some water systems, such as the Washington Aqueduct, do not use any copper sulfate at present, according to chief Ways.

Aluminum sulfate -- also know as alum -- which is used to force coagulation of solid particles.

Potassium permanganate, which helps reduce the level of manganese in the water.

Fluoride, which is added by the major Washington water systems to prevent tooth decay. Enough fluoride is added here to bring it up to the level of one part fluoride per million parts water -- the amount generally regarded by dentists and doctors as the most effective for the prevention of tooth decay.

Lime, which is added in varying amounts, depending on the acidity of the water moving through the purification process at a given time.

Chlorine, which may be added at the beginning of the treatment process or at the end. The amount added varies, depending on the plant and when it chlorinates the water.

"The aim is to have the water out in the distribution system carrying one part chlorine per million parts water," Ways said. "But because chlorine is a volatile substance, you can't keep it at one part throughout the system. It breaks down [becomes a gas and then escapes]. So you may have 1.5 parts chlorine in one part of the city and .5 parts in another part. But the average would be one part."

Besides the chlorination treatment at the plant, the water may be given additional doses as it moves through the pipelines, to kill any bacteria that may exist in the distribution network.

Sodium bisulfite, which may be added when the treatment plant analysis of the water shows that too much chlorine was added to the water. "Sodium bisulfite knocks down the chlorine level and makes the water more acceptable," said Warfield, the Fairfax County spokesman.

Sulphur dioxide, which also can reduce chlorine levels that are too high. Washington Aqueduct uses sulfur dioxide when necessary, Ways said.

Carbon, which is added occasionally to filter out the taste of any algae growth that survived the copper sulfate.

Ammonia, which Fairfax County began adding to its Occoquan Reservoir plant water about two weeks ago. Warfield said the ammonia has two benefits: It improves the quality of the water and it lowers the level of trihalomethanes.

The addition of ammonia to water has one disadvantage, however. It can kill tropical fish.

"One pet store lost all its tropical fish stock, because the ammonia changes the chlorine," Warfield said. He said the ammonia causes a chemical reaction that makes it more difficult to get chlorine out of the water. Tropical fish normally can't survive in water containing chlorine.

Fairfax County has notified 53 pet shops that stock tropical fish and recommended that they increase the dechlorination doses they add to tank water by 4 to 5 times the usual amount.

Under the new federal standards for human drinking water set by the Environmental Protection Agency, the acceptable limit for trihalomethanes, the suspected cancer-causing materials, will be 100 parts per billion parts water, based on an annual average for a system.

Water systems don't have to meet those standards until late 1981, but monitoring will begin Nov. 29. The Fairfax County Water Authority has had levels of trihalomethanes that were slightly higher than 100, Warfield said, but its average in recent years has been within the tolerance range. With the ammonia additives, the system has been under 100 parts, he said.

The Washington Suburban Sanitary Commission has been under the 100 mark for more than two years, according to spokesman Arthur Brigham. And the Washington Aqueduct also has been within the limits in its tests, said chief Ways.

"We meet and far exceed all standards," Ways said. "All the jurisdictions are in commonplace."

As for customer comments about tastes, he had this final comment: "Taste and odor are subjective judgments. Some people notice and some don't. Just like some people like Scotch and some like bourbon."