Water Treatment Company of
Maryland, Inc.

10620 Riggs Hill Road
Unit J
Jessup, Maryland

301.776.1510 FAX

The Region's
Premier Water Treatment Company


Why Water Treatment?





     ARC News

A Brief History of ARC Water Treatment (pdf)


Ed Goldstein was working with The Metropolitan Refining Company as their representative in Philadelphia in 1960 when people in the water filter business hatched the idea of selling HVAC water treatment.  This led to his forming a partnership with Joe Cohen to create Arc Water Treatment Company.  The name relates to their first location on Arch Street in Philadelphia, and they spun off from the water filter business on May 1, 1963 to create the new company that would specialize in the new water treatment industry.

The business grew in Philadelphia, gaining lots of clients and a reputation for preventive maintenance, as Ed convinced building owners and managers that treating the water circulating in their HVAC systems would prevent future corrosive degradations.  Ed’s chemical engineering degree served him well in building this new business, as he developed a reputation among design and consulting engineers, and mechanical contractors to specify water treatment as part of new building design.  Of course, as an entrepreneur building a new business, he learned the many additional skills needed to manage employees, customers, and to make it a profitable business for the long haul. Ed’s son David was completing his education at the University of Maryland, and the two of them saw an opportunity to expand Arc’s HVAC water treatment into the growing Washington DC metropolitan area.  So Arc began reaching out geographically into Maryland in 1978, and undertook special projects for a concrete molding company and a major insurance company.  This led to the establishment of an office in Beltsville, MD in the summer of 1980, just as David graduated and he began working as a full time salesman for Arc on September 1, 1980.

Arc quickly expanded at the Maryland location, partly by acquiring the accounts of the local Metropolitan Refining Company representative (who was based in Alexandria) and the business of a local water treatment company.  Some of these acquired accounts have remained as clients of Arc to this day.  The service model for all these clients was now a full service, Nordstrom-type relationship, wherein Arc Technicians would deliver chemicals, test HVAC system water, apply appropriate amounts of treatment chemicals, and repeat this biweekly to assure the customer that their systems were running efficiently.  Later they introduced automated controllers to better control water and chemical usage for cooling towers, and that enabled a change to monthly service visits.

One of Arc’s neighboring businesses in the Beltsville office was to become a major mechanical contractor in the DC region, and David worked closely with them on new projects, which became the model for further growing the Arc business.  Ed and David worked with design engineers to create a well-documented set of specifications for water treatment systems, complete with drawings and installation instructions, which engineers could incorporate into new building design.  These became the high standard for the construction industry, and Arc was the sole bidder on many new construction jobs to provide the water treatment equipment and warranty service.  This often led to
continuing relationships with building owners and managers who retained Arc for the water treatment service for many years.

Arc outgrew the Beltsville location, and moved to Jessup in June 1990, with a larger warehouse for mixing more proprietary water treatment chemicals.  Ed had worked with experts in the industry to create a variety of chemicals for cooling towers, closed loop systems, and steam boilers, so Arc now had products that would protect all hydronic systems for customers, year round.  The Jessup location also enabled Arc to provide better service to Baltimore clients, as the client base expanded throughout the two city region.  The emphasis was still on quality service and prevention, and Ed, David and Joe Cohen gave seminars to engineers at industry gatherings or in small groups throughout the mid-Atlantic.

Also in 1990, a natural separation grew between the two Arc Water Treatment businesses.  It was clear that the two families were going in different directions, so Ed and Joe agreed to separate the businesses by territory, with Joe retaining the original Philadelphia client base.  Ed was now firmly committed to growing the “southern” operation, and Arc Water Treatment Company of Maryland was formed in 1990 to do that.  By then he and David had hired Eric Hagen as another full time salesman (in 1988, along with Chuck Light as a technical sales/serviceman) and the staff had expanded to 14, including sales, service and office personnel.

Ed continued to manage Arc Water Treatment Company of Maryland through the next ten years, while David concentrated on developing relationships with mechanical contractors.  This was a highly successful strategy as the Washington DC area enjoyed a building boom and Arc grew along with the economy of the region.  The first decade of the 21st century saw the successful transition of the firm from founder Ed to son.


alum boiler

Many new hot water boiler construction projects and boiler retrofits are designed with high-efficiency aluminum core boilers. These types of boilers are very sensitive to boiler water pH, and need to be chemically treated very carefully. It is imperative that the water treatment contractor be notified as soon as possible about the installation of aluminum core boilers.

Aluminum is very susceptible to corrosion at higher pH levels, and the use of normal boiler chemicals can be very harmful to the boilers. The boiler manufacturers usually include a warning label that requires the boiler water pH range to be between 6.0 and 8.5. Normal hot water boiler water treatment for non-aluminum boilers requires a pH range of 8.0 to 10.5.

The two most common treatment chemicals (corrosion inhibitors) for hot water boilers are nitrite and molybdate.

The Problem:

*Nitrite can never be used in aluminum boilers, as it creates a very reactive and corrosive condition
in aluminum boilers. Use of nitrite will cause severe damage to aluminum boilers.

Molybdate-based corrosion inhibitors have pH enhancers to maintain the required pH range of 8.0 to 10.5 for regular boilers. Furthermore, normal untreated city water used to fill the systems already have a pH of approximately 7.5 to 8.2, limiting the amount of "pH buffer" available for the aluminum boiler upper range of 8.5 pH. When the required amount of molybdate treatment is added to the boiler system (to achieve 100-150 ppm of treatment), the resulting pH will far exceed the 8.5 pH limit.

Similarly, these new boiler systems need to be chemically pre-cleaned and flushed prior to the introduction of the regular corrosion inhibitors. Normal cleaning chemicals are very alkaline, with a pH level well above 8.5, and should also be avoided in aluminum boilers.

The Solution:

Arc encourages engineers and mechanical contractors to notify your water treatment contractor immediately if an aluminum boiler is specified and/or installed.

Arc recommends pre-cleaning aluminum boiler systems with a pH neutral detergent formulation that will not harm or react with aluminum boiler cores.

Arc also recommends the use of neutral pH corrosion inhibitors that will provide excellent corrosion protection for aluminum boiler cores and other system metallurgies.



In the current economic pressure-cooker, many properties are reviewing their operating costs for areas that would seem less essential during tight times, or may not be justified under close cost/benefit analysis. Plus the emphasis on “going green” has everyone reviewing the use of utilities (electric, gas and water) for areas where reductions can be achieved, often justified as another cost-cutting action. One maintenance service that stands up to close cost analysis is HVAC water -treatment. Whether it is treating the water in closed loop systems or in cooling towers, a good property manager or engineer knows that an effective water treatment program is money well spent. For closed loop systems, which usually require fewer chemicals once a system is commissioned, one might think that this is an area that would hit the cost-cutting block. Yet the small fee to have an independent expert verify regularly that the systems are well maintained,and continue to stay corrosion free, is well worth the peace of mind. If for no other reason, it allows building management to “sleep well” knowing their to explain to the owners that many thousands of dollars must be spent to replace internal piping before its expected life-time, simply because pipes became corroded and failed duet o saving a few pennies on critical water treatment over the years. More importantly are the hundreds or thousands of dollars saved through regular,professional chemical treatment of the water in the cooling tower. These well-spent dollars(only a few hundred a month in most cases) easily offset an annual expense of having to acid-clean condenser tubes or heat exchangers, which, without proper treatment, are the critical mechanical components that develop layers of calcium scale. A scaled heat exchange surface is much less energy-efficient, greatly reducing heat transfer and causing a huge increase in electrical costs. Similarly, a proper water treatment program will reduce corrosion in your HVAC systems,greatly extending the service life of both your equipment and building piping. The relatively few dollars spent on chemical treatment pays huge dividends if you can avoid costly repairs for many years.
Another consideration when looking at the cooling tower water treatment program, is whether to continue treating to prevent Legionnaires disease. Cooling towers are known incubators of Legionella bacteria, and if an outbreak should occur, owners of a tower without treatment would be subject to lawsuits. The protection against this situation is to maintain professional water treatment services, and include regular testing for Legionella to protect building occupants and defend against potential litigation in case of an out break. A good, comprehensive water treatment program keeps your HVAC systems clean and free from scale, corrosion and biological fouling, allowing you to maximize your system efficiency and keep your energy costs at a minimum. So avoid reducing the water treatment budget to keep from being “penny-wise, but pound foolish”.


For over 50 years, non-chemical devices (NCD) have been marketed in the water treatment industry claiming to control or eliminate scale, corrosion, deposition and microbiological growths in cooling tower and boiler systems. These devices base their claims on magnetic, electromagnetic, electrostatic or catalytic theories which sound feasible, as presented in product literature, but when the devices are field tested or subjected to legitimate scientific studies, they simply do not work.Lately these devices have been marketed with the promises of saving money, reducing costs and protecting the environment, to be part of “green technology”. This effective marketing campaign by the cooling tower manufacturers overlooks the history of failed field tests and normal value engineered costs.Several independent scientific studies and field tests have been done over the years on similar devices to evaluate their effectiveness in controlling scale, corrosion and biological growths, including the U.S. Army Corps of Engineers, Arthur Freedman Associates, Inc., Iowa State University, Milwaukee School of Engineering, and Timothy Keister, FAIC, CWT, to name a few. The conclusions of all of these studies refute the claims made by these devices, and scientifically prove that they are not an effective substitute for traditional chemical treatment of cooling towers. For example, Mr. Keister, who has examined many installed units writes, “NCD’s are not capable of producing the effects claimed in the literature”.The cost of this additional equipment can be in the tens-of-thousands of dollars range, depending on the size of the cooling towers. The initial expense of the “green” technology is considerably higher than the tried-and-true chemical treatment program. When all costs are factored in, we believe the traditional chemical water treatment program is more cost effective.Until there is proven, scientific evidence, based upon known chemical and physical science, our position about NCD’s remains the same as it has for decades: • They simply do not work as marketed. • They are much more expensive than chemical treatment systems. • The claims made are scientifically unsubstantiated. • The costs associated with them (initial costs, yearly maintenance fees and repair costs after failure) are far higher than any “green” benefits or cost savings to the buyer.
Further information about these devices is extensively documented by Professor Stephen Lower on the web at http://www.chem1.com/CQ/magscams.html. Arc Water Treatment has also developed a position paper on this issue, which may be obtained by contacting us at arc@arcwater.com or 800-832-3260.Arc Water Treatment Company has remained at the cutting edge of the chemical treatment industry for over 44 years. The chemical feeding equipment and chemical formulations currently used in the industry have evolved and are greatly improved to maximize system effectiveness and maintain environmental integrity. Chemical treatment remains the most effective and reliable method to keep your systems free from scale, corrosion and biological fouling.Please talk to one of our experts before investing in any alternative systems.


Arc Water Treatment is continually working to improve the chemicals used in our water treatment programs. In this case, we lead the industry in formulating an improved, cost-effective and more environmentally-friendly product for treating cooling towers.CTSM-2 is a re-formulation of our superb cooling tower treatment, incorporating the best and latest organic ingredients for corrosion and scale inhibition, including dispersants. CTSM-2 has reduced molybdate levels, which makes this product the latest, state-of-the-art formulation and more environmentally friendly. It still uses molybdate as a tracer to make sure that all other ingredients, such as scale inhibitors, corrosion inhibitors and dispersants are at proper levels within your system for maximum protection and efficiency.This change led us to switch how we test for molybdate. We have been using the drop test method for testing molybdate at 4 to 8 ppm levels. The drop test kits are only accurate down to 4 ppm. We will still be testing for molybdate to determine the level of protection present in your system, but at a much lower reading (0.4 - 0.8 ppm) using a hand held electronic device. This device is very accurate down to 0.1 ppm.We have incorporated the latest environmentally friendly corrosion inhibitors and scale inhibitors in our new formulation. Our new formulation also helps prevent white rust from occurring. With a lower pH in our formula, we are able to maintain a lower pH within your system. Higher pH systems can lead to white rust if the system has not been properly passivated. Moreover, with a lower pH formula, the biocides that are used will react better and be more effective at killing bacteria and algae within the system.As proof of its effectiveness, we were asked to return to a customer that had switched water treatment companies. With towers covered by white rust, we used the new CTSM-2 to super-treat the system, and the white rust and accumulated films were cleaned up in just a couple of weeks, as shown in the adjacent ‘before’ and ‘after’ pictures.
Overall, we believe we have created a more cost-effective treatment program which will also benefit your cooling tower and the environment. This is another example of how Arc is working for its customers and within its industry to ensure the latest technology and best products are applied to protect your systems. We welcome your inquiries to arc@arcwater.com or call us at 800-832-3260.


Good reasons why the answer is yes!There are several common misconceptions about closed systems. One is that closed systems are sealed off from the atmosphere and circulate the same body of fluid all the time. Therefore, they are quite stable and never need any form of chemical treatment to protect them. This is not quite true, as exemplified by automobile cooling systems which are certainly not operated with just plain water. We know what the result would be - rusty water and pretty soon, an invoice for a new water pump.The effects on a closed loop system used for any kind of heating or cooling are the same - corrosion, deterioration of components and loss of heat transfer efficiency. What causes these problems to occur?Some waters used to fill a closed loop can be acidic and contain dissolved oxygen. Low carbon steel and iron corrode rapidly under these conditions releasing small flakes of rust into the circulating stream. These particles are abrasive and tend to erode the components of the system. This can be particularly harmful in the area of pump shaft seals.
What happens after all the oxygen and acidity has been used up? Would the system become stable and corrosion cease?So-called closed loops are not truly closed. Provisions must be made to automatically compensate for any pressure changes or water losses. To accomplish this, the system will normally utilize an expansion tank (which has air inside), and relief valve, at the same time being connected to the water main via a pressure-reducing valve (PRV).The net result of this is the introduction of a small but continuous supply of acidic water containing corrosive oxygen. The problem is aggravated considerably if the system is opened for any kind of routine maintenance or component replacement. As corrosion in the loop continues, heat-transfer surfaces become coated and lose efficiency and tubes become plugged. Layers of debris lead to an effect known as under-deposit corrosion, which can cause pitting, a form of concentrated, localized corrosion. Pitting should be avoided at all costs because it leads to rapid perforation or component failure. How can you tell if system has problems?Some simple tests on the circulating water will give a very good indication of whether things are under control .Appearance- Dark brown or black water indicates a serious corrosion problem. There should be very few solid particles collecting at the bottom of the sample container.Examine the filter- See how much material is being removed.Dissolved iron and total iron tests- If the sample contains more than 1 mg/L (parts per million) iron in either of these tests, the system is corroding and needs to be brought under control as soon as possible.How can you restore control using chemical treatment?
A closed loop chemical treatment program should provide the following:pH control- Overcoming the effects of an acidic raw water supply is accomplished by a suitable pH adjustment additive.Film-forming corrosion inhibitor- Coating all internal surfaces of piping and equipment with a protective,mono-molecular film will ensure that no further attack is possible. Use a product (such as molybdate or nitrite) that is recommended for all closed systems.What else can be done to protect a closed loop system? Make sure to start with a clean system. Measure the corrosion inhibitor concentration regularly to ensure it is not being diluted. Examine the system for leaks. If leaks are suspected, installation of an inexpensive totalizing water meter in the makeup line will provide early detection. We welcome your inquiries to arc@arcwater.com or call us at 800-832-3260.


Each winter is a time for building engineers to inspect the “tubes” in the chillers as part of the annual maintenance program for their cooling tower systems. We were alerted this past winter that some of them had developed an apparent scale, so we spent severalmonths researching the type of scale and possible causes. Scaling is what proper watertreatment is supposed to prevent, so this became a high priority to solve before the nextcooling season.
Using several of our best labs and technicians, we determined most of the apparent scaling was phosphate based, occurring primarily in and around Washington, D.C. This took a lot of detective work to narrow the source and cause to a particular chemical in a limited area. It was based on samples we had analyzed from throughout our service region, from the Eastern Shore of Maryland to and beyond Dulles Airport and the growing suburbs of Northern Virginia. We then learned that the water coming from certain reservoirs had been pre-treated by the Washington D.C. Water Authority with a new phosphate chemical added to it. Perhaps this was a result of their highly-publicized lead problems from the year before. Whatever the reason, many of our customers were now using make-up water in cooling towers that had 4 ppm combined phosphates already added at the treatment plant, so with our protective chemicals also containing phosphates, the total amount of phosphates in some systems was “overloaded” and began precipitating as a phosphate scale. Fortunately, phosphate scale is relatively easy to remove, so with a thorough annual cleaning, the cooling systems were ready for another season.
We have responded to this issue by a slight reformulation in our cooling tower treatment chemical, CTSM-2. We enlisted the best minds in the water treatment industry, and made sure this reformulation didn’t reduce the overall protection that we’ve always provided. Now it gives the additional assurance that, even when make-up water is pre treated with phosphate, the cooling towers will still be protected to our high standard. We also learned during this research that some customers try to save money by running their systems extra cycles before adding make-up water. This practice increases the chances that the remaining water, after much evaporation in the towers, may contain excessive amounts of calcium carbonate, which will also begin to precipitate and form scale. This can be controlled by closely monitoring conductivity levels, by adding make-up water to keep these below the maximum level recommended by your water treatment specialist. Evaporative coolers need to be operated at even fewer cycles because of their propensity to keep the water at higher temperatures that are conducive to causing scale precipitation. We welcome your inquiries to arc@arcwater.com or call us at 800-832-3260.


To obtain occupancy permits for new buildings, as well as for additions or reworking of water systems in existing buildings, builders must prove to Inspectors that the water is safe to drink. The industry refers to the piping that supplies potable water as the domestic water system. The domestic water system must be thoroughly cleaned and the water needs to be tested and proven safe to drink, before the building can be occupied.The cleaning and testing should be done by an independent party to achieve full safety certification, and this is an important role that Arc Water Treatment is particularly qualified to perform. Similar to independent certification of elevators and sprinkler systems, the safety of the water piped to each drinking fountain, coffee machine, and sink is paramount to ensuring tenants that a building is safe to occupy.Arc Water Treatment offers to sterilize and certify the safety of the domestic water systems, and does this daily for Mechanical and Plumbing Contractors. Our Service Technicians are all fully Certified by the State of Maryland to take water samples, and handle them properly for analysis by an independent laboratory, which is also fully certified to assess the safety of the water for drinking purposes. The procedure involves injecting a strong solution of chlorine into the new piping at the source, and ensuring the chlorine reaches every fixture on the system. Our highly trained Technicians have test chemicals to verify the chlorine will sterilize all parts of the domestic water system, and must remain in contact of all parts for at least three hours, as prescribed by the American Water Works Association C651 Plumbing Code. They then fully flush the system, testing again at every fixture to ensure only city water remains in the system. After flushing, a sample of the water is taken, treated with a Thiosulfate pill to ensure test validity, sealed and documented for the lab with a “chain of custody” form.
The independent laboratory tests this certified sample primarily for the presence of fecal coliforms, and provides a Certificate of Analysis to document whether the sample is within EPA standards for drinking water. Arc Water Treatment then forwards the results, stamped with the seal of our Professional Engineer, to the contractor who needs this independent certification that the water is safe to drink, often as the final step to obtaining the occupancy permit.The sterilizing program is particularly active this time of year for contractors completing modernizations or building of new schools. It is vital that the water in the schools be certified as safe to drink before students are allowed in the buildings, and Arc Water Treatment works closely with many plumbers and mechanical contractors to get this done on time.

The best review of non-chemical devices paper written in recent years!(pdf)

“Best Practices for Cooling Water Management”
Published by AWT. A position paper on Green Treatments. (pdf)