X4 (Electric Blue)
X4 (Passion Red)
X4 (Yale Blue)
X4 (Splender Lilac)
X4 (Electric Blue) : Counter-Top
X4 (Passion Red) : Counter-Top
X4 (Yale Blue) : Counter-Top
X4 (Splender Lilac) : Counter-Top
Total Score out of 100
X4 (Electric Blue) : 71
X4 (Passion Red) : 71
X4 (Yale Blue) : 71
X4 (Splender Lilac) : 71
Purification Capacity Per Hour
X4 (Electric Blue) : 15 Ltr/hr
X4 (Passion Red) : 15 Ltr/hr
X4 (Yale Blue) : 15 Ltr/hr
X4 (Splender Lilac) : 15 Ltr/hr
MRP (Rs)
X4 (Electric Blue) : 16750
X4 (Passion Red) : 16750
X4 (Yale Blue) : 16750
X4 (Splender Lilac) : 16750
X4 (Electric Blue) : RO
X4 (Passion Red) : RO
X4 (Yale Blue) : RO
X4 (Splender Lilac) : RO
RO: Reverse Osmosis
Power Consumption
X4 (Electric Blue) : 48 W
X4 (Passion Red) : 48 W
X4 (Yale Blue) : 48 W
X4 (Splender Lilac) : 48 W
X4 (Electric Blue) : 
X4 (Passion Red) : 
X4 (Yale Blue) : 
X4 (Splender Lilac) : 
Tank Capacity
X4 (Electric Blue) : 9 L
X4 (Passion Red) : 9 L
X4 (Yale Blue) : 9 L
X4 (Splender Lilac) : 9 L
Manufactured/Marketed by
X4 (Electric Blue) : A.O Smith India Water Products Pvt. Ltd
X4 (Passion Red) : A.O Smith India Water Products Pvt. Ltd
X4 (Yale Blue) : A.O Smith India Water Products Pvt. Ltd
X4 (Splender Lilac) : A.O Smith India Water Products Pvt. Ltd
X4 (Electric Blue) : Non-Electric
X4 (Passion Red) : Non-Electric
X4 (Yale Blue) : Non-Electric
X4 (Splender Lilac) : Non-Electric
X4 (Electric Blue) : 12
X4 (Passion Red) : 
X4 (Yale Blue) : 
X4 (Splender Lilac) : 
Number of Purification Stages
X4 (Electric Blue) : 5
X4 (Passion Red) : 5
X4 (Yale Blue) : 5
X4 (Splender Lilac) : 5
X4 (Electric Blue) : White and Blue
X4 (Passion Red) : Passion Red
X4 (Yale Blue) : Yale Blue
X4 (Splender Lilac) : Splender Lilac
Material of Body
X4 (Electric Blue) : Plastic parts
X4 (Passion Red) : Plastic parts
X4 (Yale Blue) : Plastic parts
X4 (Splender Lilac) : Plastic parts
X4 (Electric Blue) : Post-RO Carbon Filter, Pre-Filter, Pre-RO Carbon Filter
X4 (Passion Red) : Post-RO Carbon Filter, Pre-Filter, Pre-RO Carbon Filter
X4 (Yale Blue) : Post-RO Carbon Filter, Pre-Filter, Pre-RO Carbon Filter
X4 (Splender Lilac) : Post-RO Carbon Filter, Pre-Filter, Pre-RO Carbon Filter
Post-RO Carbon Filter: Last level of purification acts like a polisher and enhances the taste of purified water.
Pre-RO Carbon Filter: Removes chlorine and organic impurities like harmful pesticides. It also adsorbs bad taste and odour-causing organic compounds from water.
TDS Reduction
X4 (Electric Blue) : ≥95 approx
X4 (Passion Red) : ≥95 approx
X4 (Yale Blue) : ≥95 approx
X4 (Splender Lilac) : ≥95 approx
% Water Recovery
X4 (Electric Blue) : 30
X4 (Passion Red) : 30
X4 (Yale Blue) : 30
X4 (Splender Lilac) : 30
Weight and Dimensions
Net Weight
X4 (Electric Blue) : 8.8 kg
X4 (Passion Red) : 8.8 kg
X4 (Yale Blue) : 8.8 kg
X4 (Splender Lilac) : 8.8 kg
X4 (Electric Blue) : 314 mm
X4 (Passion Red) : 314 mm
X4 (Yale Blue) : 314 mm
X4 (Splender Lilac) : 314 mm
X4 (Electric Blue) : 325 mm
X4 (Passion Red) : 325 mm
X4 (Yale Blue) : 325 mm
X4 (Splender Lilac) : 325 mm
X4 (Electric Blue) : 503 mm
X4 (Passion Red) : 503 mm
X4 (Yale Blue) : 503 mm
X4 (Splender Lilac) : 503 mm
Input Voltage
X4 (Electric Blue) : 150 – 300 VAC/ 50 Hz
X4 (Passion Red) : 150 – 300 VAC/ 50 Hz
X4 (Yale Blue) : 150 – 300 VAC/ 50 Hz
X4 (Splender Lilac) : 150 – 300 VAC/ 50 Hz

The Bureau of Indian Standards (BIS) has specified requirements for removal/reduction ofheavy metals in IS:16240. We tested the 10 brands for presence of the following heavy metals:

Arsenic: As many as six brands – Tata Swach, Zero B, Kent, Aquaguard, Electrolux and Usha – did not meet the requirement (a maximum 0.01 mg/l).

Copper: None of the brands met the requirement set by Indian Standard (0.05 mg/l).

Mercuy: All the brands more or less met the specified requirement – minor deviations were observed in Pureit, Aquaguard and Usha.

Cadmium: Minor deviation was observed in one brand, Pureit. All other brands met the standard requirement.

Iron: All the brands met the requirements, with the exception of deviation in two brands, Whirlpool and Usha.

Lead and chromium: All brands met the requirements.

Score out of 14 (for all toxic metals)
X4 (Electric Blue) : 12.48
X4 (Passion Red) : 12.48
X4 (Yale Blue) : 12.48
X4 (Splender Lilac) : 12.48
Physicochemical Parameters
X4 (Electric Blue) : 3.91
X4 (Passion Red) : 3.91
X4 (Yale Blue) : 3.91
X4 (Splender Lilac) : 3.91
Total dissolved solids (TDS) refer to the combined content of all inorganic and organic substance contained in a liquid; these are present in a molecular, iodised, or micro-granular suspended form. RO systems are specifically designed to effectively remove TDS to a great extent. Where the TDS level of supply/ground water is high, from 1,000 up to 2,500–3,000, it is recommended that RO systems be installed for drinking-water purpose. A special cellulose membrane cartridge plays a key role in removing TDS from the input water.

As per Indian Standard, an RO system shall reduce TDS level of feed water to less than or equal to 500 mg/l.

  • Al brands reduced the TDS to below the limit specified (500 mg/l) when the input level was maintained at a fixed level.
  • Tata Swach scored highest on this parameter, followed by Aquaguard.
  • Some brands reduced the TDS level to below 100, which is also not desirable due to their reducing the intake level of essential minerals.

X4 (Electric Blue) : 3.84
X4 (Passion Red) : 3.84
X4 (Yale Blue) : 3.84
X4 (Splender Lilac) : 3.84
This refers to the amount of dissolved solid particles that are suspended in the water and that cause light rays shining through the water to scatter. Thus, turbidity makes the water cloudy or even opaque in extreme cases.

The turbidity of drinking water should not be more than 5 NTU and ideally be below 1 NTU. This is a key quality indicator for a water filter/purifier.

  • All the brands were able to remove turbidity to a level that makes it safe and suitable for drinking.
  • Kent, Whirlpool, LG and Tata Swach could remove 100 per cent turbidity and scored highest on this parameter.
X4 (Electric Blue) : 3.28
X4 (Passion Red) : 3.28
X4 (Yale Blue) : 3.28
X4 (Splender Lilac) : 3.28
As per Indian Standard, the minimum recovery of product water shall be equal to or more than 20 per cent. So, waste water should not be more than 80%.
  • Waste water was in the range of 62 per cent–71.4 per cent. This means the recovery of water in all brands was well above the prescribed limit of 20%.

RO and RO+UV water purifiers produce a lot of waste water during the purification process. Thus, if you pass four litres of water through an RO purifier, it will produce just about one litre of potable water. All the impurities are concentrated in the waste water and hence it is not drinkable.

Can the Waste Be Used?

a) First thing: test the TDS in the waste-water stream. If the TDS is below 1,000, you can use the water in your plants.

b) Alternately, mix some of that water with tap water to mop the house. Make sure you dilute it with tap water because if the TDS is high and you use just the RO waste to mop the floor, you may see some salt deposition after the water dries.

c) You can use the waste water to clean the sewage pipe at home or kitchen because of its saline nature..

d) You can use it to flush toilets.

X4 (Electric Blue) : 4
X4 (Passion Red) : 4
X4 (Yale Blue) : 4
X4 (Splender Lilac) : 4
Taste and odour of output water should be acceptable; in other words, there should not be any bad odour or taste.

All the brands gave output water with agreeable taste and odour.

X4 (Electric Blue) : 2.75
X4 (Passion Red) : 2.75
X4 (Yale Blue) : 2.75
X4 (Splender Lilac) : 2.75

pH is a measure of the acidity or alkalinity of a solution. Aqueous solutions at 25 degrees C with a pH less than 7 are considered to be acidic, while those with a pH greater than 7 are considered to be basic (alkaline). When pH level is 7.0, it is defined as neutral at 25 degrees C.

As per Indian Standard, the pH of drinking water shall be 6.5 to 8.5.

Four brands – LG, Pureit, Zero B and Tata Swach – showed slight deviation from the pH requirement for drinking water.

X4 (Electric Blue) : 2.97
X4 (Passion Red) : 2.97
X4 (Yale Blue) : 2.97
X4 (Splender Lilac) : 2.97
Water hardness denotes the presence of chloride and sulphates of calcium and magnesium salts in water. It is usually expressed in milligrams per litre of dissolved calcium and magnesium carbonate. Calcium and magnesium enter water mainly through the weathering of rocks. The more calcium and magnesium in water, the harder the water.
  • The lowest percentages of hardness reduction were found in Usha (96.88), Zero B (98.89) and Whirlpool (98.89).
  • All other brands reduced hardness by more than 99 per cent
  • X4 (Electric Blue) : 2
    X4 (Passion Red) : 2
    X4 (Yale Blue) : 2
    X4 (Splender Lilac) : 2
    The presence of residual chlorine in drinking water indicates that a sufficient amount of chlorine added initially to the water to inactivate bacteria and certain viruses that cause diarrhoea, as well as to ensure that the water is protected from recontamination. Residues of chlorine must be absent in the output water of water purifiers. This test was conducted after all other tests.
    • All the brands were able to reduce 100 per cent residual chlorine.

    The presence of bacteria and pathogenic (disease causing) organisms is a concern when considering the safety of drinking water. Pathogenic organisms can cause intestinal infections, dysentery, hepatitis, typhoid fever, cholera and other illnesses. As per the BIS requirement, the RO purifier shall inactivate/kill the selected standard challenging organism E. coli.

    X4 (Electric Blue) : 99.9
    X4 (Passion Red) : 99.9
    X4 (Yale Blue) : 99.9
    X4 (Splender Lilac) : 99.9

    When E. coli exceeds the permissible level in water, consumers are advised to boil the water they use for cooking and drinking, and even for brushing teeth. As per Indian Standard, the requirement is 99.9999 percentage reduction in E. coli. We observed all tested brands for four consecutive weeks to check percantage reduction in E. coli levels.

  • None of the brands we tested.met the requirements of Indian Standard for E. coli reduction. Hence, none of these RO water filters can be said to be completely safe for drinking.
  • E. coli Score out of 16
    X4 (Electric Blue) : 4.44
    X4 (Passion Red) : 4.44
    X4 (Yale Blue) : 4.44
    X4 (Splender Lilac) : 4.44
    X4 (Electric Blue) : 99.5 cfu/100ml
    X4 (Passion Red) : 99.5 cfu/100ml
    X4 (Yale Blue) : 99.5 cfu/100ml
    X4 (Splender Lilac) : 99.5 cfu/100ml

    A microorganism smaller than bacteria, the MS2 virus cannot grow or reproduce apart from in a living cell. Viruses are the smallest agents of disease, and perhaps the most problematic, because they are as minute as 0.04 u (micron). Viruses cause many common human infections and are also responsible for a bevy of rare diseases. Viruses can infect all types of life forms, from animals and plants to bacteria and archaea.

    Based on the requirement specified by IS: 16240,MS2 virus was spiked in input water and the output sample was tested to check the virus-removal efficiency of purifiers.

    • None of the brands we tested met the requirement of Indian Standard for removal of MS2 virus. Hence, none of these RO water filters can be said to be completely safe for drinking.
    MS2 Virus Score out of 16
    X4 (Electric Blue) : 4.2
    X4 (Passion Red) : 4.2
    X4 (Yale Blue) : 4.2
    X4 (Splender Lilac) : 4.2
    X4 (Electric Blue) : Able to reduce the pesticide residues
    X4 (Passion Red) : Able to reduce the pesticide residues
    X4 (Yale Blue) : Able to reduce the pesticide residues
    X4 (Splender Lilac) : Able to reduce the pesticide residues
    • In India, high concentrations of both organochlorine and organophosphorous pesticides have been found in surface and ground water samples. Reverse-osmosis water filters are expected to remove pesticide residues.
    • We tested the 10 brands for pesticide residues. They were all able to reduce the pesticide residues and scored equally well.
    General Qualities
    X4 (Electric Blue) : 4
    X4 (Passion Red) : 4
    X4 (Yale Blue) : 4
    X4 (Splender Lilac) : 4
    Water-storage capacity should be as declared by the manufacturer.
    • In five brands – Tata Swach, Electrolux, Usha, Aquaguard and Pureit – the water-storage capacity was found to be less than the declared.
    X4 (Electric Blue) : 5
    X4 (Passion Red) : 5
    X4 (Yale Blue) : 5
    X4 (Splender Lilac) : 5
    All the brands scored equally well.
    X4 (Electric Blue) : 2.4
    X4 (Passion Red) : 2.4
    X4 (Yale Blue) : 2.4
    X4 (Splender Lilac) : 2.4
    It is the quantity of output water released from the system in a particular time period. Production rate should not be less than five litres per hour.
    X4 (Electric Blue) : 3.8
    X4 (Passion Red) : 3.8
    X4 (Yale Blue) : 3.8
    X4 (Splender Lilac) : 3.8
    Overall, the workmanship and finish ranged from good to very good.
    X4 (Electric Blue) : 3
    X4 (Passion Red) : 3
    X4 (Yale Blue) : 3
    X4 (Splender Lilac) : 3
    As per BIS requirement, a nameplate shall be fixed on the body of the RO system at a prominent location. The nameplate shall be marked with these details:
    • Name of manufacturer
    • Brand name
    • Production serial number
    • Model name or code
    • Production rate in l/h
    • Percent recovery of product water
    • Maximum operating TDS level
    • Supply voltage, whether single- or three-phase, frequency, volts and wattage

    The product should include these details as well: namely address of manufacturer, manufacturing date, MRP, and warning/precaution note. An instruction manual containing proper method of operation and use of the purifier shall be supplied along with the purifier. The purifier may also be marked with the Standard mark.

    All the brands had provided the required information

    X4 (Electric Blue) : 2
    X4 (Passion Red) : 2
    X4 (Yale Blue) : 2
    X4 (Splender Lilac) : 2
    As per the national standard, packing of RO purifier shall be sufficiently robust to give adequate protection from transportation damage. Being made from plastic material, the product has delicate assemblies and housing.
    • All the water purifiers were packed in thick, laminated paperboard carton supported by good-quality thermocol to give protection from damage.
    X4 (Electric Blue) : 2
    X4 (Passion Red) : 2
    X4 (Yale Blue) : 2
    X4 (Splender Lilac) : 2
    A user’s manual for proper method of operation and use of the RO system shall be supplied along with the product. It shall also include details on the life and specification of all the filters/ consumables.
    • In the case of Aquaguard, no manual was provided with the unit.