Why Your Ferric Chloride Dose Keeps Climbing: The Sponge Mechanism Behind Phosphorus Removal, and How to Size It
Table of Contents
What you will learn
Ferric chloride removes phosphorus from wastewater mainly by adsorption onto hydrous ferric oxide, which is why the iron-to-phosphorus dose climbs from about 1:1 above 1 mg/L effluent P to 2:1 or more at lower targets. This guide gives the iron content per gallon for 10–40% solutions, works EPA’s 1 MGD dosing and sludge examples (74.8 gal/day, 315 lb/day), quantifies alkalinity consumption (0.93 mg CaCO₃ per mg FeCl₃), explains pre-, co- and post-precipitation, and covers sulfide control in collection systems.
Every operator who has run ferric chloride for phosphorus has watched the same thing happen. The first dose, sized from the textbook one-iron-per-phosphorus reaction, gets you most of the way. Then the permit tightens, or the effluent target drops below a milligram per litre, and the dose has to double, then double again, for a gain that keeps shrinking. That is not a bad batch of chemical and it is not a bad jar test. It is the chemistry telling you that you are not precipitating a salt. You are building a sponge — and the article below is about what that means for the drum count, the alkalinity, the sludge line and the lift station upstream.
Why does the ferric chloride dose climb as the phosphorus target drops?
The dose climbs because ferric chloride removes phosphorus mostly by adsorption onto freshly formed hydrous ferric oxide, not by a clean one-to-one precipitation of iron phosphate. The textbook reaction is real but it is the minority pathway. The U.S. EPA’s Nutrient Control Design Manual (2010) puts it plainly: at effluent phosphorus above about 1.0 mg/L, plants observe something close to the stoichiometric 1:1 iron-to-phosphorus ratio, and “the molar ratio typically increases well above the stoichiometric ratio as lower effluent phosphorus concentrations are needed.”
The reason, documented by Szabó et al. (2008) and Smith et al. (2008) and adopted by the EPA manual as the working model, is a surface-complexation mechanism. When ferric chloride hits water at wastewater pH, the iron hydrolyses almost instantly into hydrous ferric oxide (HFO), a floc of iron-oxygen-hydroxide with an enormous surface area. Phosphate binds to that surface by sharing an oxygen with an iron atom:
Two things follow from that, and both show up on your chemical invoice.
First, the sponge fills up. Removal is limited by available surface sites, not by how much iron is in the water. As you push toward 0.5, 0.3 or 0.1 mg/L, each remaining milligram of phosphate has fewer sites to find, so you add more floc to create more surface. That is the bend in the dose curve, and no supplier’s product will straighten it.
Second, the sponge ages. The EPA manual notes that under rapid mixing, surface sites are readily available, but with slow mixing “much of the HFO would form in the absence of phosphorus and result in less efficient phosphorus removal.” Aged floc has fewer reactive sites. Iron that hydrolyses in a quiet channel before it meets phosphate is iron you paid for and did not use.
The operational consequence: a good rapid-mix at the injection point is worth more than a higher dose. Inject into turbulence — a weir drop, a pipe with a static mixer, the aeration basin inlet — not into a slow channel. The same gallons remove more phosphorus when the iron and the phosphate meet in the first second.
How much iron is actually in the drum?
A gallon of 40% ferric chloride solution contains about 1.64 pounds of iron; a 55-gallon drum carries roughly 90 pounds of iron and a 330-gallon tote about 540. Those are the numbers a dose calculation actually needs, and they are surprisingly hard to find on a spec sheet, which reports concentration as weight-percent FeCl3 and leaves the arithmetic to you.
The conversion is straightforward. Iron is 55.845 of ferric chloride’s 162.20 molecular weight, or 34.4% of it. Multiply the solution’s specific gravity by its weight fraction of FeCl3, then by 0.344:
Specific gravities are the values on our product specifications; EPA’s worked examples use 1.4 for 40% and land within 2% of the same answer. The table makes the freight question obvious. Iron is what you are buying, and the water it arrives in is what you are paying to ship. Per pound of iron delivered, 40% is the cheapest concentration to move by a wide margin, which is why it is the municipal standard and the concentration in every EPA example below.
When a lower concentration is the right call anyway. A small package plant or a lift station feeding a few gallons a day cannot run a metering pump at a sensible stroke on 40%. Dropping to 10% or 20% puts the pump in the middle of its range, makes the dose repeatable, and is worth the freight on a few drums a year. Match the concentration to the pump, not to the price per gallon.
How do you size the initial dose? EPA’s 1 MGD example, worked
For a 1.0 MGD plant with 4 mg/L of phosphorus entering the secondary clarifier, EPA’s design example arrives at 74.8 gallons per day of 40% ferric chloride to remove up to 98% of the phosphate. The example is worth following line by line, because it is the calculation every plant repeats with its own numbers, and it is where the sponge mechanism first shows up as a design choice.
- Iron per litre of solution. 0.40 × 1.4 kg/L = 0.56 kg FeCl3/L; × (55.85 ÷ 162.2) = 0.193 kg Fe/L.
- Choose the molar ratio. EPA uses 2.0 mol Fe per mol P as the basis for 98% removal — twice stoichiometric, for exactly the surface-site reason above. That is 2 × (55.85 ÷ 30.97) = 3.61 kg of iron per kg of phosphorus.
- Solution per kg of phosphorus. 3.61 kg Fe ÷ 0.193 kg Fe/L = 18.7 L of solution per kg P.
- Daily volume. 3.785 million L/d × 4 mg/L × 18.7 L/kg ÷ 106 = 283 L/d = 74.8 gal/day.
Scale it to your plant by replacing the flow and the influent phosphorus. At 5 MGD and 6 mg/L it is 561 gal/day, a tote every four days. At 0.25 MGD and 3 mg/L it is 14 gal/day, a drum every four days. The ratio in step 2 is the lever: the EPA manual reports that for tertiary polishing below 0.10 mg/L, the required dose “can be 2 to 3 times” the secondary-treatment dose, which is the curve bending again.
This is an initial design estimate, not a set point. EPA is explicit that the reactions “are complex and difficult to generalize” and that jar testing should set the final dose and mixing conditions for the specific wastewater. Run the jar test before you commit to a tote schedule; the calculation tells you which drum sizes to have on the shelf while you do.
Where should ferric chloride be added: pre-, co- or post-precipitation?
Ferric chloride can be dosed ahead of the primary clarifier, into the biological process, or after secondary clarification, and each point trades removal efficiency against sludge and cost differently. EPA’s Chapter 9 names the three and it is worth using the names, because they show up in permits and engineering reports.
- Pre-precipitation — chemical added to raw wastewater ahead of primary sedimentation, with the precipitate leaving in primary sludge. It also pulls extra suspended solids and BOD out of the primaries, which lightens the load on the biological stage.
- Co-precipitation (simultaneous precipitation) — chemical added directly to the biomass, typically at the aeration basin or the mixed liquor channel, with iron phosphate leaving in the waste activated sludge. This is the most common retrofit because it needs no new tankage.
- Post-precipitation — chemical added after secondary clarification, with solids removed in a tertiary clarifier or filter. It is the point of choice for very low effluent limits, because it handles the smallest phosphorus load with the cleanest water and the fewest competing solids.
Many plants dose at two points, and EPA also notes that chemical can be added to sidestreams and return flows to stop phosphorus released during sludge handling from circling back to the head of the plant. If your dose keeps creeping up and the influent has not changed, look at the centrate or the filtrate return before you look at the chemical.
What does ferric chloride do to alkalinity and pH?
Every milligram per litre of ferric chloride destroys about 0.93 mg/L of alkalinity expressed as calcium carbonate. The iron hydrolyses, and each Fe3+ consumes three bicarbonate ions on its way to hydroxide:
Three equivalents of alkalinity per mole of iron is 150 g of CaCO3 for every 162.2 g of FeCl3, or 0.926 to one. Expressed per unit of iron, it is 2.69 mg of CaCO3 per mg of Fe. On the EPA example plant that is a modest bill; on a soft-water plant that is also nitrifying — which itself consumes alkalinity — it can be the difference between a stable pH and a crash that stalls the nitrifiers.
Watch alkalinity before you watch phosphorus. If residual alkalinity is heading toward the 40 to 70 mg/L range EPA associates with nitrification stress, ferric chloride will get there faster. Budget caustic or lime alongside the ferric, or shift the dose point so the biological stage sees less of the iron.
The 40% product itself is strongly acidic; the solution pH is typically below 2, and it is classified as a corrosive. That matters for feed equipment and for the neighbourhood of the injection point, but a properly mixed dose is diluted into the flow within seconds and the alkalinity effect above, not the raw acidity, is what the process sees.
How much extra sludge does ferric chloride make?
On EPA’s 1 MGD example, the 74.8 gal/day dose produces about 315 lb/day of additional inorganic solids that would not exist without the chemical. That figure comes from EPA Example 9-2, which assumes the phosphorus leaves as an iron-phosphate-hydroxide solid (Fe1.6H2PO4(OH)3.8) and the surplus iron leaves as Fe(OH)3: 37.8 mg/L of new solids, times 8.34, times 1.0 MGD.
Framed as a percentage, EPA reports that dosing to the secondary process at roughly twice stoichiometric for a 0.5 to 1.0 mg/L effluent target raises secondary sludge production by 35 to 45 percent and total plant sludge by 5 to 25 percent. Pre-precipitation runs higher: primary sludge up 50 to 100 percent, total plant sludge up 60 to 70 percent, partly offset by a lighter secondary stage. Tertiary polishing to below 0.10 mg/L uses a higher ratio on a much smaller phosphorus load, for a 10 to 40 percent increase plant-wide.
Two practical notes. Iron sludge dewaters well and is dense, so the volume increase is smaller than the mass increase suggests. And the iron does not disappear in the digester: iron-bound phosphorus tends to stay largely bound through anaerobic digestion, which is why plants that dose ferric chloride upstream often see less phosphorus in the centrate than plants relying on biological removal alone.
Does ferric chloride control hydrogen sulfide too?
Yes — the same iron that captures phosphate precipitates dissolved sulfide, which is why ferric chloride is dosed at lift stations and force-main inlets to control odour and the corrosion that follows it. The mechanism is a two-step one that the sewer-chemistry literature (Nielsen et al., 2005) has mapped in detail: ferric iron first oxidises sulfide to elemental sulfur while being reduced to ferrous iron, and the ferrous iron then precipitates remaining sulfide as iron sulfide.
On paper that is 1.16 lb of iron per lb of sulfide. In a real sewer the number is much higher: practitioners commonly dose 2 to 6 lb of iron per lb of hydrogen sulfide, and Nielsen et al. (2008) found that reaching a dissolved sulfide residual below 0.2 mg/L is difficult even at around 20 g of iron per g of sulfide, because the iron is also consumed by organic matter, by oxygen in turbulent reaches, and by the phosphate that is present in every domestic sewer.
That last point is the interesting one. Gutierrez et al. (2010) showed that iron dosed into a collection system for sulfide control arrives at the treatment plant still carrying its phosphorus-removal capacity, and measurably reduces the phosphorus load left for the plant to remove. A utility that pays for ferric chloride at the lift station is buying part of its phosphorus permit compliance at the same time. Size the sewer program and the plant program together and the total iron is lower than the two sized apart.
Ferric or ferrous? Ferrous chloride precipitates sulfide directly and is often used where sulfide is the only target. Ferric chloride oxidises first, precipitates second, and brings the phosphorus capacity with it. Nielsen’s full-scale work found a blend of the two more effective than either alone. If you are already buying ferric for the plant, running it at the lift station simplifies the inventory to one drum.
Which concentration and pack size should a plant specify?
Specify 40% in the largest container your feed room can safely receive, unless a low daily dose or a small metering pump argues for a dilute grade. Every concentration we stock is the same chemistry — iron(III) chloride in water, supplied as Technical Grade with a lot-specific certificate of analysis on request — so the choice is entirely about logistics and feed equipment.
| Situation | Concentration | Container | Why |
|---|---|---|---|
| Municipal plant, 1 MGD and up | 40% | 275 or 330-gallon IBC tote | Most iron per shipped pound; tote-to-day-tank transfer keeps the feed room simple. |
| Package plant, industrial pretreatment, 0.1–1 MGD | 40% or 30% | 55-gallon drum or 5-gallon pail | A drum every few days at typical loads; drums rotate stock before it ages. |
| Lift station, force-main inlet | 40% | 55-gallon drum on a spill pallet | Sulfide dosing is continuous and small; one drum type shared with the plant. |
| Very low daily dose, small metering pump | 10% or 20% | 1-gallon case or 5-gallon pail | Keeps the pump in its accurate stroke range; repeatable dose beats cheap freight. |
| Jar testing, pilot, lab | 40% | 1 quart or 1 gallon | Dilute to a 1% working stock; one bottle covers a full dose-response series. |
Materials of construction
Ferric chloride solution is a corrosive Class 8 hazmat (UN 2582), and it is a chloride, which is the part people underestimate. It attacks carbon steel outright and it pits stainless steel, including 316; do not run it through a stainless day tank or stainless fittings expecting them to last. The standard materials are HDPE and polypropylene for tanks and totes, PVC and CPVC for piping, PTFE or Viton for pump diaphragms and seals, and rubber-lined or FRP construction for large storage. Keep it out of direct sunlight in translucent containers and it stores well; the solution is stable in a closed container, but a partially emptied tote will slowly pick up moisture and drift in concentration, which is another argument for buying the size you turn over.
Run the jar test before you buy the tote
A jar test costs an afternoon and a quart of product, and EPA calls it the fast, low-cost way to find the optimum dose and mixing conditions for a specific wastewater. The dose calculation above tells you the neighbourhood; the jar test tells you the address. Set up a series at 1.0, 1.5, 2.0 and 3.0 molar Fe:P from the calculation, flash-mix for 30 seconds, flocculate for 15 minutes, settle for 30, and measure orthophosphate in the supernatant. Where the curve flattens is your operating ratio. Then do it again at a different pH and a different rapid-mix speed, because those two variables are the ones the sponge mechanism cares about most.
Common questions
Why is a 2:1 iron-to-phosphorus ratio used when the reaction is 1:1?
Because most of the phosphorus is removed by adsorption onto hydrous ferric oxide rather than by direct FePO₄ precipitation. Adsorption is limited by available surface sites, so more floc — more iron — is needed as the effluent target drops. EPA’s design examples use 2.0 mol Fe per mol P for 98% removal at secondary treatment, and note that tertiary polishing below 0.1 mg/L can need two to three times that.
How much phosphorus does one gallon of 40% ferric chloride remove?
At the EPA design ratio of 2:1 molar, one gallon of 40% ferric chloride (about 1.64 lb of iron, or 0.744 kg) removes roughly 0.45 lb (0.21 kg) of phosphorus. At 1:1 stoichiometric it would be twice that, but 1:1 only holds when the effluent target is above about 1 mg/L.
How many gallons of ferric chloride does a 1 MGD plant use per day?
EPA’s worked example gives 74.8 gal/day of 40% solution for a 1.0 MGD plant with 4 mg/L phosphorus entering the secondary clarifier, dosed at 2:1 molar for 98% removal. Scale linearly with flow and with influent phosphorus, then confirm by jar test.
Does ferric chloride lower pH and consume alkalinity?
Yes. Each mg/L of FeCl₃ consumes about 0.93 mg/L of alkalinity as CaCO₃ (2.69 mg per mg of iron). The effect is significant on soft, low-alkalinity wastewater and on plants that are also nitrifying, which consumes alkalinity independently. Plan supplemental alkalinity if residual alkalinity is trending toward 40 to 70 mg/L.
How much extra sludge does chemical phosphorus removal with ferric chloride produce?
EPA reports a 35 to 45 percent increase in secondary sludge and a 5 to 25 percent increase in total plant sludge when dosing the secondary process at roughly twice stoichiometric for a 0.5 to 1.0 mg/L effluent. On the 1 MGD example this is about 315 lb/day of additional inorganic solids.
Where in the plant should ferric chloride be added?
At the primary clarifier influent (pre-precipitation), into the biological process (co-precipitation), or after secondary clarification ahead of a tertiary filter or clarifier (post-precipitation). Co-precipitation is the most common retrofit; post-precipitation is used for very low limits. Inject at a point of strong turbulence in every case.
Can ferric chloride be used for hydrogen sulfide and odour control in sewers?
Yes. Ferric iron oxidises dissolved sulfide to elemental sulfur and the resulting ferrous iron precipitates remaining sulfide as FeS. Field doses typically run 2 to 6 lb of iron per lb of H₂S, well above the 1.16 stoichiometric ratio, because iron is also consumed by organics, oxygen and phosphate. Iron dosed in the sewer also arrives at the plant still removing phosphorus.
What is the difference between the 10, 20, 30 and 40% products?
Only the water. All four are iron(III) chloride in aqueous solution, CAS 7705-08-0, supplied as Technical Grade. Forty percent carries the most iron per shipped gallon (about 1.64 lb) and is the municipal standard; the dilute grades exist for small metering pumps and low daily doses where feed accuracy matters more than freight.
Is this product suitable for drinking water treatment?
This guide covers wastewater and collection systems. Coagulants used in drinking water treatment in the United States are generally required to meet NSF/ANSI/CAN 60; confirm the certification status of any product with your supplier and your state primacy agency before use in a drinking water system.
References & Authoritative Sources
Dosing ratios, worked examples, sludge and alkalinity figures are drawn from the U.S. EPA’s Nutrient Control Design Manual; chemical identity from PubChem; sulfide chemistry from the peer-reviewed sewer-process literature.
- U.S. EPA, Nutrient Control Design Manual, EPA/600/R-10/100, August 2010 — §3.3.2 surface-complexation mechanism (Eq. 3-3) and dose-ratio behaviour; §3.5 sludge production; §9.3 points of application; Examples 9-1 (74.8 gal/d) and 9-2 (315 lb/d).
- PubChem CID 24380: Ferric chloride (iron trichloride) — National Center for Biotechnology Information. CAS 7705-08-0, molecular formula Cl3Fe, molecular weight 162.20 g/mol.
- Smith, S., Takacs, I., Murthy, S., Daigger, G.T. and Szabó, A. (2008). Phosphate complexation model and its implications for chemical phosphorus removal. Water Environment Research 80(5): 428–438. Cited by EPA as the basis of the HFO surface-complexation model.
- Szabó, A., Takacs, I., Murthy, S., Daigger, G.T., Licskó, I. and Smith, S. (2008). Significance of design and operational variables in chemical phosphorus removal. Water Environment Research 80(5): 407–416.
- Nielsen, A.H., Lens, P., Vollertsen, J. and Hvitved-Jacobsen, T. (2005). Sulfide–iron interactions in domestic wastewater from a gravity sewer. Water Research 39(12): 2747–2755. — ferric oxidation of sulfide to elemental sulfur followed by ferrous precipitation of FeS.
- Nielsen, A.H., Hvitved-Jacobsen, T. and Vollertsen, J. (2008). Control of sulfide in sewer systems by dosage of iron salts. Science of the Total Environment 394(1): 162–170. — ≈20 g Fe per g S required; residual below 0.2 mg/L difficult to reach.
- Gutierrez, O., Park, D., Sharma, K.R. and Yuan, Z. (2010). Iron salts dosage for sulfide control in sewers induces chemical phosphorus removal during wastewater treatment. Water Research 44(11): 3467–3475.
- U.S. EPA, Design Manual: Odor and Corrosion Control in Sanitary Sewerage Systems and Treatment Plants, EPA/625/1-85/018, 1985.
- Iron-per-gallon figures are computed from the specific gravities on Alliance Chemical’s product specifications (1.092, 1.195, 1.31, 1.43 for 10, 20, 30 and 40% w/w) and the PubChem molecular weights above; alkalinity consumption from the hydrolysis stoichiometry (3 HCO3− per Fe3+, 50 g CaCO3 per equivalent).
Need ferric chloride for a plant, a pretreatment system or a lift station?
All four concentrations, with live pricing from quarts through drums and IBC totes. If you are not sure whether your feed pump wants 40% or 20%, send the daily dose and the pump model and we will tell you which one to buy.
Key numbers and sources
| Fact | Value | Source |
|---|---|---|
| CAS number of ferric chloride | 7705-08-0 | pubchem.ncbi.nlm.nih.gov |
| Molecular weight of FeCl₃ | 162.20 g/mol | pubchem.ncbi.nlm.nih.gov |
| Iron fraction of FeCl₃ by mass | 34.4% | pubchem.ncbi.nlm.nih.gov (55.845 ÷ 162.20) |
| Iron per gallon, 40% solution (SG 1.43) | 1.64 lb | Computed; product specification |
| EPA design Fe:P molar ratio, 98% removal | 2.0 | epa.gov (NCDM 2010) Ex. 9-1 |
| Iron required per kg P at 2:1 molar | 3.61 kg | epa.gov (NCDM 2010) Ex. 9-1 |
| 40% FeCl₃ dose, 1.0 MGD, 4 mg/L P | 74.8 gal/day | epa.gov (NCDM 2010) Ex. 9-1 |
| Additional sludge, same example | 315 lb/day (37.8 mg/L) | epa.gov (NCDM 2010) Ex. 9-2 |
| Secondary sludge increase, ~2× stoichiometric | 35–45% | epa.gov (NCDM 2010) §3.5 |
| Alkalinity consumed per mg FeCl₃ | 0.93 mg as CaCO₃ | Hydrolysis stoichiometry |
| Stoichiometric Fe:S for sulfide precipitation | 1.16 by mass | 2Fe³⁺ + 3S²⁻ → 2FeS + S |
| Iron needed for sulfide residual < 0.2 mg/L | ≈20 g Fe per g S | Nielsen et al. 2008 |
| UN number, ferric chloride solution | UN 2582, Class 8 | 49 CFR 172.101 |
Frequently Asked Questions
Why is a 2:1 iron-to-phosphorus ratio used when the reaction is 1:1?
Because most of the phosphorus is removed by adsorption onto hydrous ferric oxide rather than by direct FePO₄ precipitation. Adsorption is limited by available surface sites, so more floc — more iron — is needed as the effluent target drops. EPA’s design examples use 2.0 mol Fe per mol P for 98% removal at secondary treatment, and note that tertiary polishing below 0.1 mg/L can need two to three times that.
How much phosphorus does one gallon of 40% ferric chloride remove?
At the EPA design ratio of 2:1 molar, one gallon of 40% ferric chloride (about 1.64 lb of iron, or 0.744 kg) removes roughly 0.45 lb (0.21 kg) of phosphorus. At 1:1 stoichiometric it would be twice that, but 1:1 only holds when the effluent target is above about 1 mg/L.
How many gallons of ferric chloride does a 1 MGD plant use per day?
EPA’s worked example gives 74.8 gal/day of 40% solution for a 1.0 MGD plant with 4 mg/L phosphorus entering the secondary clarifier, dosed at 2:1 molar for 98% removal. Scale linearly with flow and with influent phosphorus, then confirm by jar test.
Does ferric chloride lower pH and consume alkalinity?
Yes. Each mg/L of FeCl₃ consumes about 0.93 mg/L of alkalinity as CaCO₃ (2.69 mg per mg of iron). The effect is significant on soft, low-alkalinity wastewater and on plants that are also nitrifying, which consumes alkalinity independently. Plan supplemental alkalinity if residual alkalinity is trending toward 40 to 70 mg/L.
How much extra sludge does chemical phosphorus removal with ferric chloride produce?
EPA reports a 35 to 45 percent increase in secondary sludge and a 5 to 25 percent increase in total plant sludge when dosing the secondary process at roughly twice stoichiometric for a 0.5 to 1.0 mg/L effluent. On the 1 MGD example this is about 315 lb/day of additional inorganic solids.
Where in the plant should ferric chloride be added?
At the primary clarifier influent (pre-precipitation), into the biological process (co-precipitation), or after secondary clarification ahead of a tertiary filter or clarifier (post-precipitation). Co-precipitation is the most common retrofit; post-precipitation is used for very low limits. Inject at a point of strong turbulence in every case.
Can ferric chloride be used for hydrogen sulfide and odour control in sewers?
Yes. Ferric iron oxidises dissolved sulfide to elemental sulfur and the resulting ferrous iron precipitates remaining sulfide as FeS. Field doses typically run 2 to 6 lb of iron per lb of H₂S, well above the 1.16 stoichiometric ratio, because iron is also consumed by organics, oxygen and phosphate. Iron dosed in the sewer also arrives at the plant still removing phosphorus.
What is the difference between the 10, 20, 30 and 40% products?
Only the water. All four are iron(III) chloride in aqueous solution, CAS 7705-08-0, supplied as Technical Grade. Forty percent carries the most iron per shipped gallon (about 1.64 lb) and is the municipal standard; the dilute grades exist for small metering pumps and low daily doses where feed accuracy matters more than freight.
Is this product suitable for drinking water treatment?
This guide covers wastewater and collection systems. Coagulants used in drinking water treatment in the United States are generally required to meet NSF/ANSI/CAN 60; confirm the certification status of any product with your supplier and your state primacy agency before use in a drinking water system.
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