Power Washing and Roof Cleaning Forum

Art O · Approved Exterior Cleaner

Pure water vs tap water for window cleaning test

Zach Maynard · Approved Exterior Cleaner

Is that 480PPM water! Geez my tap water is like 80 PPM.

Patrick G · Approved Exterior Cleaner

This is gonna be me this spring!

mistersqueegee · Approved Window Cleaner

I average 300-400 TDS here. Multi stage filtration is a necessity for me.

Art O · Approved Exterior Cleaner

What is TDS (Total Dissolved Solids)? Where does it come from, why is it important and how to treat it?

(TDS) Total Dissolved Solids are the total weight of all solids that are dissolved in a given volume of water, expressed in units of mg per unit volume of water (mg/L), also referred to as parts per million (PPM).

Questions and Answers about TDS in your water:

What are Total Dissolved Solids?
Where do Dissolved Solids come from?
Why should you measure the TDS levels in your water?
How do you reduce or remove the TDS in your water?
How do I check Reverse Osmosis membrane performance with this TDS meter?

What Are Total Dissolved Solids - TDS?

1. "Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water. This includes anything present in water other than the pure water (H20) molecule and suspended solids. (Suspended solids are any particles/substances that are neither dissolved nor settled in the water, such as wood pulp.)

2. In general, the total dissolved solids concentration is the sum of the cations (positively charged) and anions (negatively charged) ions in the water.

3. Parts per Million (ppm) is the weight-to-weight ratio of any ion to water.

4. Conductivity is usually about 100 times the total cations or anions expressed as equivalents. Total dissolved solids (TDS) in ppm usually ranges from 0.5 to 1.0 times the electrical conductivity.

Where do Dissolved Solids come from?

1. Some dissolved solids come from organic sources such as leaves, silt, plankton, and industrial waste and sewage. Other sources come from runoff from urban areas, road salts used on street during the winter, and fertilizers and pesticides used on lawns and farms.

2. Dissolved solids also come from inorganic materials such as rocks and air that may contain calcium bicarbonate, nitrogen, iron phosphorous, sulfur, and other minerals. Many of these materials form salts, which are compounds that contain both a metal and a nonmetal. Salts usually dissolve in water forming ions. Ions are particles that have a positive or negative charge.

3. Water may also pick up metals such as lead or copper as they travel through pipes used to distribute water to consumers.

Why Should You Measure the TDS level in your Water?

The EPA Secondary Regulations advise a maximum contamination level (MCL) of 500mg/liter (500 parts per million (ppm)) for TDS. Numerous water supplies exceed this level. When TDS levels exceed 1000mg/L it is generally considered unfit for human consumption. A high level of TDS is an indicator of potential concerns, and warrants further investigation. Most often, high levels of TDS are caused by the presence of potassium, chlorides and sodium. These ions have little or no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate and others) may also be dissolved in the water.

The following are reasons why it is helpful to constantly test for TDS:

Taste/Health	High TDS results in undesirable taste which could be salty, bitter, or metallic. It could also indicate the presence of toxic minerals. The EPA's recommended maximum of TDS in water is 500mg/L (500ppm).
Filter performance	Test your water to make sure the filter system has a high rejection rate and know when to change your filter (or membrane) cartridges.
Hardness	High TDS indicates Hard water, which causes scale buildup in pipes and valves, inhibiting performance.
Aquaculture	A constant level of minerals is necessary for aquatic life. The water in an aquarium should have the same levels of TDS and pH as the fish and reef's original habitat.
Hydroponics	TDS is the best measurement of the nutrient concentration in a hydroponics' solution.
Pools and Spas	TDS levels must be monitored to prevent maintenance problems.
Commercial/Industrial	High TDS levels could impede the functions of certain applications.

Ideal Drinking water from reverse osmosis, distillation, deionization, microfiltration, etc..	0-50 PPM
Often considered acceptable range for carbon filtration, mountain springs or aquifers.	50-140 PPM
Average tap water.	140-400 PPM
Hard water.	170 PPM or above
Less desirable	200-300 PPM
Unpleasant levels from tap water, aquifers or mountain springs.	300-500 PPM
The EPA's maximum contamination level.	500 PPM

How do you reduce or remove the TDS in your water?

1. Carbon Filters (very slight reduction)

2. Reverse Osmosis (R.O.) (extremely high reduction and great tasting water )

3. Distillation (total reduction - flat taste)

4. DI Deionization (usually a final polishing filter following a RO Reverse Osmosis filtration system to eliminate TDS)

TDS Meters are simple to use to check Reverse Osmosis membrane performance. Measure the incoming water and the RO water. Divide the larger number into the smaller number and subtract that decimal from 1. The resulting decimal is the percent of TDS that the membrane is removing. Anyone that wants to know about the quality of their water should have one of these TDS Meter Testers.

Membrane TDS Rejection Percentage Calculator

Enter Supply
Feed TDS

Enter RO Permeate
TDS

Your Membrane Rejection Rate:
%

(This indicates your membrane's performance. Replace the RO membrane once the rejection rate falls below 80%)

Art O · Approved Exterior Cleaner

Pure Water Training : What is TDS ?