WATER – CULINARY

INTRODUCTION

The original purpose of pressurized water was to prevent fires not to provide drinking water to the population.  Drinking water, more technically referred to as culinary water or potable water was always a nice added benefit of a public water supply, but preventing the entire neighborhood from going up in flames was the real incentive.

It started with the Great Fire of London in the year 1666 which destroyed most of the city.  The Great Fire of London showed how vulnerable even the nicest cities were to a single fire.  The city of London did not want to have to rebuild again.  Along with the new buildings came a new underground system of water pipes, all built of wood.  There were markings on the streets to indicate the location of the water mains, sort of like the first line markers.  Whenever there was a fire, the fire crews had to quickly dig up the street, find the wooden water pipe, then hammer a “fire plug” into the wood, which would allow the water to pour out in to a puddle, then hauled by bucket to the building that was on fire.

There was of course a great necessity to provide drinking water to the cities but that water was usually carted in on wagons.  In about 1810 a man named Benhu Johnson was delivering water to the people of Cleveland, Ohio, at that time a tiny town with a population of 57 people.  Johnson gathered water from Lake Erie in barrels, then sold it in town at a cost of 2 gallons for a penny.  Today the city of Cleveland delivers pressurized and treated water to its citizens for about 15 gallons a penny.

A few cities did see the importance of pressurized water early on.  Philadelphia began a pressurized water system starting around 1801.  By 1815 there were 63 homes connected to the original wooden water pipes, and 37 iron fire hydrants.  Today the Philadelphia Water Department serves 1.5 million residents, has 27,700 fire hydrants, and 3,300 miles of water mains.

WATER PLANT LAYOUT

A water plant can be constructed in a number of different ways.  The main issues for each city or town are not only size, but the availability of ground water, surface water (lakes, rivers, reservoirs, etc.), and the terrain.  Many small towns use only a single well as a water supply, while large cities may use multiple wells, plus a reservoir or two, as well as pulling water from a nearby lake or river.  Most cities will use multiple water sources, not just one.  In a town that uses only ground water (from wells) there may or may not be a treatment plant, but surface water requires treatment of some kind because it is more likely to contain contaminants.

Distribution water is commonly operating in the range of 65 to 75 psi.  Service pipes actually can operate in a wider range, from about 45 to 80 psi.  However, there can be quite a variety of pressures because of the wide range of pipe materials that have been used.

The distribution part of any water system begins at the storage facility: tanks, water towers, or large vaults.  The maximum water pressure is decided by the position of the tank, and is the reason most water tanks are placed in an elevated position, and why they are usually referred to as a water “tower”.  In some mountainous areas the water tanks may be right at ground level, but at a higher ground elevation than the city, but in most towns the water tanks are one of the most noticeable features.  Those tanks will always have at least two pipes, the incoming pipe from the wells or treatment plant, and the outgoing pipe for distribution.  The outgoing pipe will be coming down from the center of the tower, and is usually smaller than the incoming pipe.  This increases the water pressure from the tower.

Many cities have had to find alternative methods of not only bringing a great deal of water in to the city, but also ensuring that the water lines had the necessary pressure to operate.  The popularity of high-rise buildings beginning in the first part of the 20th century created a problem for water pressure that would be high enough to push the water up to the top floors.  That problem was resolved at the time by installing water towers on the tops of the buildings.  High rise buildings from the 1910’s to about the 1940’s were being built with smaller water tanks on the roof to provide pressure for that particular building.  It worked well, but it gave the urban landscapes a very cluttered appearance.

Modern water supply across town or to high rise buildings was improved by the use of pump stations, also called a pump house.  A small town may not have any, while a large city may have dozens.  They are usually a small brick building with a manhole just outside the building for shut off, and these are a good connection point for locating the water pipes.  The buildings are usually identified in some way as “water department”, “PUD” for Public Utility Department, or some other indicator, and usually inside of a gated and locked fence.

PRESSURE ZONES

A small city can usually be fed from a single water tower or tank if it can be placed in a position to provide pressure across the entire area.  If not, then pump stations need to be added to increase the pressure at the far ends of town.  This results in a variety of possibilities for each town or city.  A town may have one or two wells that are pumped to a single water tower, and then service the entire town off of the force of gravity from the tower, and without any treatment plant.  On the other hand, a large city may be using a dozen wells, 2 reservoirs, as well as river water.  All of this may be pumped to multiple treatment plants, and then distributed using numerous pump stations.  The terrain as well as the size of the city has a major impact on how many pump stations are needed.  A large flat terrain will require more pump stations, as do the number of high-rise buildings, and each area served by a pump station is usually referred to as a pressure zone. 

Snohomish, Washington is a good example of a small city water supply.  They have two pressure zones, and they receive their water from two different sources.  A dam 16 miles from town diverts water to a treatment plant for the south pressure zone, which is then stored at two reservoirs.  The north pressure zone pulls water from a separate source, in to a separate treatment plant, and is then stored in a large water tower.

On the other hand, Dallas, Texas is one of the largest cities in America, and has 17 pressure zones.  Their water sources include wells, manmade lakes, the Trinity River, and 6 reservoirs.  They are also now working on a 147-mile pipeline to bring in additional water for the rapidly growing area.  There are 3 large treatment plants which send treated water to 9 water towers, 11 ground tanks, and 78 water vaults, using 28 pump stations.

 

WATER DEPARTMENTS

Water departments in North America are almost always a municipal utility.  They may be owned and operated by either the city or the county, but usually one of the two.  Often a city will have both, the city owns the water system within the incorporated part of the city, while the county owns a separate water system which serves the outer regions, and probably the outlying areas of a number of towns.  Those city and county water lines will be in close proximity in many areas, and probably even cross each other on several different streets.  They may connect at some point, and maybe not.  It all depends on the arrangements made between the city and county governments.

There are always areas which do not use the public water supply.  Many homes in either rural areas, or on the outskirts of a town will often use cisterns or individual wells for their water.  The water goes from the well in the backyard, directly in to the house.  As long as there are no nearby gas tanks or other possible contaminants, ground water is typically quite safe to drink without treatment of any kind.  If the utility prints do not show a water service to a particular building, it may be from an error in the utility records, but it may also be that the house has its own water supply

 

METERS – CURB STOPS

Water meters are small hand hole flush mounted boxes.  Older meters may be rectangular iron, while most modern meters are a round structure with iron lids.  A water meter, the same as any utility meter, is the crossover point between ownership of the utility.  From the building to the meter is owned by the property owner, from the meter upstream is owned by the water department.

A curb stop is actually a shut off valve for the water, but whether the curb stop is part of the meter assembly, or separate from it depends on the specific water department.  In some regions there is no water meter at all, just a curb stop.  These are usually in rural Western areas smaller towns.  Each subscriber pays the same amount every month.  In some areas with metered water, there may still be a separate curb stop as well, slightly farther towards the street than the meter.  This creates 3 possible scenarios for meter/curb stop arrangements: meter and curb stop, meter only, or curb stop only.

CORP STOP

A Corporation stop, or corp stop, is a shut-off valve placed where the service pipe connects with the water main.  The purpose is to allow the service line to be connected to the main without having to shut off the water main.  Once the service is connected, the corp stop remains in place, and yet it no longer serves a purpose.

GANG METERS

Gang Meters are multiple water meters that feed off of a single water service pipe.  The service pipe is laid across the street, and then branches to several meters, sometimes 2, 3, 4, or more.  It can be difficult to determine the exact position where that single service pipe connects with the separate services from the meters, but it will be in a flow chart configuration, not a “4 pipes blending in to one”.  So, the individual pipes from the meters will come straight out, then tap in to a cross pipe, and the cross pipe will have a single connection with the service from across the street.

AMR

Like power and gas companies, water departments used to employ a sizeable number of meter readers to check each meter every month for the actual usage by the customer.  Yet, more than any other utility, water departments have been moving away from having large numbers of employees to walk every street in town on a monthly basis, or bi-monthly basis.

An option was to read the meters automatically.  However, this was only possible with culinary water because water meters are close to the street, but gas and electric meters are usually attached to the building.

The change was made possible by a process called AMR (Automated Meter Reading).  This has become the most noticeable sign of a water meter, a black rubber button, usually about 2 to 3 inches in diameter, that is attached to the top of the meter.  That button sends a signal which can be detected several yards away.  Municipalities that utilize AMR also purchase a truck or van with a side mounted sensor which can detect the signal from the antenna, and read the meter without anyone getting out of the truck, or even stopping.  Each antenna (button) can be identified separately, and its water usage recorded automatically.  This allows for a reading of thousands of meters by a single individual who only drives the van.

Another point on AMR systems is that some of them do not use a lid attached antenna, but instead have a remote antenna which is placed in a position to face the street.  In these cases, the antennas are usually a black plastic box in an oval shape, and may be attached to walls, separate small wooden posts, fence posts, and they can even be found nailed to tree trunks.  There will still be a wire attached to the meter itself, but that wire will not come up to the lid.  They will be placed exiting the meter box below ground, then run underground to the area where the antenna box is positioned, and then up to the box.

 

WATER VALVES

Where ever there are water lines, there will also be water valves, and usually a lot of them.  Between water valves and fire hydrants, it is hard not to know when there is a water line on a given street.  When a water pipe is broken, or receiving maintenance, it is crucial to keep the rest of the system under pressure in case of a fire.  Water valves allow the operator to rapidly shut off sections of the pipe, and bypass the busted section through rerouting.

Since the very purpose of water valves is to shut off water going downstream, they are commonly placed at 3-way connections in the water system.  In this way the downstream water can be shut off in two separate directions or just one.  This results in the common site of two water valves and a 3-way connection, all placed very close together.  In fact, this often leads to the incorrect conclusion that the 3-way is itself one of the valves.

So, despite the fact that they are commonly grouped close together, a 3-way pipe connection and a water valve will never be one and the same.  A water valve will always be an in and out device.  The 3-way connection will always be a separate structure from any valve.

 

PIPE DEPTH

Water pipes are the only utility whose depth varies greatly depending on which part of the country you are in.  The main concern with depth is the frost level in the region.  In the southern portion of North America the frost line is either very shallow or non existent, all depending on how cold the temperature can be in the winter.  Many regions in the south only rarely experience temperatures below freezing, so there is no need to bury water pipes more than a few feet.  However, in some northern regions the temperature in the winter time can be as low as -28 F, and the water pipes must be placed very deep to prevent freezing.  While phone, power, gas, and other utility lines may be 2 to 4 feet in any area, water pipes are sometimes only 2 feet deep in the south, but can be as much as 10 feet or more in northern areas.  The recommended depth of water mains is 2 ½ feet from the northern end of the California coast, going down and around the south, and up halfway through North Carolina.  At the other end of the spectrum, much of Canada, as well as portions of North Dakota and Minnesota, have a recommended depth of 8 feet.  Some of the northern regions may only bury their lines at 8 feet, but many water pipes in areas where the recommendation is 7 feet may bury them much deeper than that to ensure that they don’t freeze.

 

WATER KEYS & EXTENSIONS

Deep water pipes present a problem of access when trying to shut the water off.  Even at a four- or five-foot depth the nut is too far down to reach by hand.  The municipal employees will need to have access to the nut for shutting off the water if necessary.

The water is turned on or off by the use of a water key, a simple metal rod with a U-shaped bottom end, but water keys are usually only produced in lengths of no more than 6 feet.  So, deep water valves often have extensions placed on the top of the valve so that the water key can reach the top of the extension, which can be turned, and turns the valve nut along with it.

PRV AND ARV

A Pressure Release Valve (PRV) is a device that allows excess water pressure to be released automatically.  All pipes have a maximum pressure load, and once that limit is reached the PRV diverts some of the water to the above ground pipe where it may create quite a splash, but it will be aimed downward towards the concrete pad to limit the danger.

Some PRVs are rather sizable and include a manhole connection nearby.  Large PRVs may be quite visible aboveground as just a large candy cane shaped pipe.

The water pipes will have a 3-way connection within the manhole, and a pipe extending to the above ground structure which usually includes a U-shaped pipe coming out of the ground, and usually mounted on a concrete pad.

Other PRVs are rather small, only a few feet high.  Smaller PRVs are usually contained within a metal cage or housing of some kind.  These are manufactured by a variety of manufacturers so there is a great diversity in their appearance.

An Air Release Valve (ARV) is used for allowing air to escape from a pressurized water pipe.  Anyone who has ever lived in an old house, or moved in to a house that has been sitting unused for some time has experienced the clattering noise that comes with air build up inside a pressurized water pipe.  It often sounds like the pipes are about to break whenever the water is turned on.  Any upward, and then downward water flow can allow air to accumulate inside the pipe, and of course it will accumulate at the high point of the pipe.  As water moves through the pipe, it is constantly slamming in to an air pocket and creating a good deal of noise.

This becomes a much bigger problem for water mains, so that air needs to be allowed an exit point.  ARVs are usually found at the crest of a hill, or any other place where the air has a tendency to build up.  An ARV sometimes uses only a small hose for the release of the air, and usually attached to a rounded keg type structure in a small handhole.  The hose may be just lying within the handhole since it does not need to be pointed in any particular direction.  The actual ARV is the keg type structure inside the handhole, and with the hose usually connected at the very top.

Both ARVs and PRVs are usually protected in metal enclosures, though it often depends on the neighborhood.  The metal enclosure is to prevent vandalism, so an ARV in a residential neighborhood may only have a plastic enclosure.

Some water departments use PRVs and ARVs quite extensively, while others do not use them at all.  This is often because of the terrain.  A city in a flat terrain may not have much use for either one since the terrain itself helps to prevent excessive water pressure, and air build up.

Many PRVs and ARVs can also be very similar in appearance so it is often not easy to tell them apart.  However, PRVs are going to be at the base of a sloped terrain, and ARVs are going to be at the crest of the hill.

 

BACKFLOW PREVENTION DEVICE

If the pressure on the water supply drops for any reason, even something as simple as several open hydrants down the street fighting a fire, then the water pressure on the services can be higher than the pressure on the main.  This allows water to flow upstream, in to the water supply.  There can be contaminants from leaking pipes and other issues, and that drop on the distribution line has the potential to literally suck contaminants from the soil and other areas in to the distribution system.

Backflow prevention devices do not all operate in the same way, except that they all prevent the water from being pulled upstream.  They can be installed directly on the water main at strategic locations, and usually for 4-inch water pipes and larger.

Backflow preventors are also installed on water services, especially for properties that have large grass areas and use a great deal of water.  This can be at schools, industrial parks, and other areas.  In this case the preventor is much smaller than a distribution device, and they will always be placed downstream from the water meter, and inside of the private property.

 

TERMINOLOGY

 

AMR (AUTOMATIC METER READING)

A system for reading water meters by the use of remote sensors.  Specially equipped trucks can drive down a street and remotely detect the water usage of an individual meter.  The meter itself requires a small antenna connection, either on top of the meter lid, or with some systems, attached to walls or posts but facing the street.  AMR antennas on meter lids are usually contained in a round rubber or plastic knob.  Those that face the street are usually in an oval plastic box.

 

ARV  (AIR RELEASE VALVE)

An ARV allows an escape for air bubbles within a pipe system.

 

BACKFLOW PREVENTION

A device installed in-line on water pipes to prevent the backflow of possible contaminants if the pressure on a section of the main drops.  These can be on main line pipes, or on services.

 

CORPORATE STOP

A shut-off valve at the connection of the service pipe to the distribution pipe.

 

CURB STOP

The shut off point for water services that are not metered.

 

GANG METER

A set of two or more water meters that are being fed from a single service pipe.  They are usually placed no more than a foot apart from each other.

 

HYDRANT

Any feature for allowing access to a water supply by the fire department.  Also known as “fire plugs” in some areas.  Hydrants can be either dry barrel or wet barrel depending on the possibility of freezing temperatures in the area.

 

METER

Most water services in North America are metered, the meter box being a round or rectangular flush mounted structure.  The meter is also the crossover point between private and public utility ownership.  Water departments that do not meter the water usage will use only a curb stop.

 

PRESSURE ZONE

Water supplies are commonly divided in to pressure zones with separate water sources, water tanks, and pump stations.  A very small town may have only one zone, while a large city may have more than a dozen.

 

PRV (PRESSURE RELEASE VALVE)

A device for allowing excess water pressure to escape from the system without damaging the pipes.  Some cities use multiple PRVs, while other cities do not use them at all.  Also sometimes called “blow offs”.

 

PUMP STATION

A small building housing a massive pump for adding water pressure to the downstream pipes.  These are usually in brick buildings which are gated and locked, and usually have a 3-phase electrical power line for operation of the pump.

 

TREATMENT PLANT

Water treatment plants are the first downstream feature of a public water supply.  They are most commonly used for any water supply that uses surface water, such as lakes, rivers, dams, etc., which can be more polluted than well water.

 

VALVE

All water supplies use numerous valves for controlling the flow of the utility.  The valves are underground with an open sleeve between the valve and the lid that covers the valve area.

 

WATER KEY

An iron rod with a wide handle at one end, and small U-shaped configuration on the other.  Water keys are used to turn water valves on or off.  They are available at most hardware stores.

 

WELL

Water wells provide ground water to water systems.  Municipal water operations may use any number of water wells as a source, sometimes by themselves, or in addition to dams, rivers, etc.  In rural areas wells may also be small and used for providing water to a single house.