Cast Iron vs Stainless Steel Water Pump

Cast Iron vs Stainless Steel Water Pump: Which one is Best?

You have decided to buy a water pump. Without this, your home is not fit for living or you can’t set up your factory. But the thing is what type of water pump you will buy? Will your water pump be made with cast iron or with stainless steel?

To answer this question or to reach you a decision there are some points for you on cast iron vs stainless steel water pump. But before knowing about these pumps let’s have some knowledge about what cast iron and stainless steel are.

Cast Iron

Wayne PC4 Cast Iron Portable Electric Water Removal Pump, Black
  • Hands-Free Water Removal - This 1/2 HP WAYNE water removal pump is the perfect tool. WAYNE model PC4 is non-submersible and has a rugged, cast-iron pump and motor housing.
  • Tough And Durable - All cast-iron construction that provides long life in tough applications.
  • Efficient Design - The integrated handle makes it easy to carry. Features brass 3/4” garden hose adapters at inlet and discharge.
  • Usage - Able to handle flat areas like basements, driveways, etc. as well as draining hot water heaters and flushing water lines.
  • Quality You Deserve - Proudly assembled in the USA with foreign and domestic parts for quality you can trust. Warrantied for 1 year for dependable, efficient performance.

Cast iron is an alloy of iron, 1.8–4% carbon, 1–3% silicon, and a very small percentage of manganese, chromium, molybdenum, titanium, and vanadium. It is brittle, melts in low temperatures, corrodes easily, has rust, low cost, has excellent machinability, is resistant to deformation, is difficult to weld, etc.

Stainless Steel

1.6 HP Stainless Steel Lawn Sprinkling Pump Electric Water Pump Transfer Pump Shallow Well Pump Garden Lawn Irrigation Booster Pump
  • Power: 1200W/1.6HP; Capacity: 3200L/H; Max Suction Height: 23 feet; Max Height: 137 Feet; Max Flow Rate: 845GPH.
  • 845 Gallon Per Hour rating tackles any draining job at a fraction of the time. 66 PSI water pressure makes this pump perfect for irrigation, water transport or pump water. Ideal for sprinkling systems, flow irrigation systems, gardening, rain barrels, large aquariums and ground water.
  • This Electric Centrifugal Clear Water Pump with 66 PSI water pressure is capable of pumping water 42 meters high with an impressive flow rate of 3200L per hour and have a maximum suction depth of 7m. It also works with a water temperature up to 35°.
  • The water pump is compatible with a tank and can work as a sprinkler pump, a well pump with a pressure regulator or a booster pump, which can be widely applied in garden, lawn and farm.
  • Portable Self-aspirating Jet Garden Pump features with stainless Aluminum pump housing, maintenance-free capacitor motor, hydraulic unit consisting of Nonyl, safe&waterproof on/off switch and easy carry handle for portability. Both size of inlet and outlet are 1 Inch while one check valve and two connectors are included.

Stainless steel is an alloy of iron, chromium at least 11%, carbon 0.03%-more than 1%, nitrogen, aluminium, sulfur, titanium, nickel, copper, selenium, niobium, and molybdenum. To get better rust-resistant quality of steel the percentage of chromium, nickel, and molybdenum has to increase. Among these chromium is the most powerful rust protective metal. Stainless steel is resistant to corrosion & stain, low maintenance, shiny, strong, high-cost melts in high temperatures, and machinability is lower than iron.

Now let us know some of the characteristics of Cast Iron vs Stainless Steel Water Pumps:

  1. Cast iron pumps corrode easily; on the other hand, stainless steel does corrode.
  2. A cast iron pump is cheaper than a stainless steel pump.
  3. If a cast iron pump pumps brackish water, alkaline, acid, and other industrial water, it will be eroded. But a good stainless steel pump can pump all these types of liquids along with tap water without erosion.
  4. A stainless steel pump is used where strength of steel and corrosion resistance are needed. But the cast iron pump is not as strong as the stainless steel pump.
  5. Water pumped by the cast iron pump can be polluted but for stainless steel, there is no chance like that.
  6. A stainless steel pump is costlier than a cast iron pump.

The advantages of using a stainless steel water pump are manifold. It can pump water for long periods and too long distances without any corrosion. As stainless steel is strong, men can depend on its durability easily.

In manufacturing stainless steel pumps, advanced technology is being used. Moreover, increasing the percentage of chromium, nickel, and molybdenum, stainless steel’s corrosion-resisting power can be increased. This virtue has made this metal so popular among users.

Without so much maintenance a stainless steel pump runs for a long time. Though it is somewhat costlier than the cast iron pump, it uses less electricity than that. It is more efficient than a cast iron pump. Stainless steel’s lifespan is much wider than cast iron. Now manufacturers are using stainless steel to manufacture different kinds of water pumps like sump pumps, submersible pumps, centrifugal pumps, plunger pumps, gear pumps, self-priming pumps, etc.

All these kinds of pumps meet all kinds of home and industry needs with more hydraulic efficiency. Stainless steel can be welded easily which is a great favor.

Day by day the stainless steel pump is replacing the cast iron pump. The former type is occupying the market widely. To maintain the quality of the water or any kind of fluid stainless steel water pump is inevitable. Without any pollution of the liquid and corrosion of the propeller or other parts, stainless steel can perform excellently for a long time.

From the above text, you have come to know the differences between cast iron pumps and stainless steel pumps. I think it will be better for you to listen to some comments from a water pump expert who has a lot of experience with it.


Will a cast iron pump rust?

Answer: Yes, a cast iron pump will become rusty. It will corrode gradually but very slowly.

Why pump casing is cast iron?

Most of the time pump casing is cast iron because it has excellent machinability. Ductile cast iron and malleable cast irons are wear resistance and vibration-dumping. It is heat resistant and tough. It absorbs internal temperature and distributes it outside. It is cheaper than stainless steel also.

Can cast iron pumps be used with potable water?

Yes, the cast iron pump can be used with potable water. But there is a chance of polluting it because cast iron has rust and corrodes gradually. Though the corrosion rate is very slow.

What is the material of water pump?

Any kind of cast iron or any grade of stainless steel can be the material of a water pump. But while you buy a water pump, bear in mind that the casing, propeller, and other parts that contact water should be non-corrosive, wear-resistant, heat-resistant, etc.

How do you clean a cast iron water pump?

Firstly, to remove sticky and grime residue, apply mineral oil. After the oil is set, wipe it with a towel. Secondly, to remove rust, use a wire brush, and scrub pump with gentle strokes. Then wipe the dust with a towel. Thirdly, you can use dishwashing detergent with warm water.

Should I paint my new water pump?

If the casing of your water pump is built with cast iron then it’ll be better to paint that. Because it’ll protect the pump from rusting and from cumulating sticky residue.

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