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Quick answer from a licensed plumber: For a counted number when sizing a softener, use the Hach 5-EP drop-count kit: each drop is 1 grain per gallon, from 1 to 30 gpg, so you get a whole number. For a fast check, Varify’s strips read in 30 seconds on a 0 to 25 gpg chart. JNW Direct’s 150-strip pack suits regular softener checks. Divide ppm by 17.1 for grains per gallon.
Our pick for sizing a softener: the Hach Total Hardness Test Kit, Model 5-EP. Check the Hach 5-EP on Amazon
Sizing a water softener starts with your hardness in grains per gallon. A test kit gets you that number at home, and the same kit tells you later whether the softener is still doing its job. This page compares a drop-count kit from Hach and three strip kits, each sold on Amazon by its maker’s own store on October 4, 2026. For what the numbers mean, see our water hardness scale.
Water Hardness Test Kits Compared
| Kit | Method | Range (maker or listing) | Tests in the kit | Time to read | Sold by |
|---|---|---|---|---|---|
| Hach 5-EP | Drop-count titration | 1 to 30 gpg, 1 drop = 1 gpg | About 100 | Count drops to a pink-to-blue change | Hach Company |
| Varify hardness kit | Dip strip, color chart | 0 to 25 gpg, 0 to 425 ppm | 100, 150 or 50 (sources differ) | 30 seconds | Varify |
| JNW Direct 150-strip kit | Dip strip, color chart | Not published by the maker | 150 | Dip and compare | JNW Direct |
| Varify 17-in-1 kit | Dip strip, 17 parameters | Includes total hardness | 100 strips + 2 bacteria tests | About 1 minute; bacteria 48 hours | Varify |
Figures from Hach’s 5-EP procedure and product page, Varify’s and JNW Direct’s product pages, and the Amazon listings we link. Each linked kit was in stock and sold by its maker’s Amazon store on October 4, 2026.
Drops or Strips?
A drop-count kit is a small titration. You measure a sample, add a reagent that turns it pink, then add titrant drop by drop until it turns blue. Hach’s 5-EP reads 1 gpg per drop, so you get a whole number. A strip has a pad that changes color, and you match it to the kit’s color chart. Strips are faster and simpler; the drop kit gives a counted number.
Plumber’s note: a strip is enough to size a softener for most homes. Use the drop kit when the reading lands between two softener sizes or you are on a well, and keep strips around for quick checks after the softener is installed.
How to Test So the Number Is Useful
- Test raw water for sizing. Plumber’s note: take the sample from a tap that is not on a softener or filter yet. If a softener is already installed, put it in bypass first or use an unsoftened tap.
- Use the right units. Our softener sizing guide works in grains per gallon. Hach says 1 gpg is 17.1 mg/L, so divide a ppm or mg/L reading by 17.1.
- Watch for iron on a well. Hach’s procedure says high iron or manganese turns the sample orange-brown and gives extra steps for it. If your fixtures show rust stains, read our softener picks for well water before you buy.
- Check the softener later. Test a softened tap and an unsoftened one. A softened tap that reads close to the raw water means the softener needs attention.
Once you have the number, the sizing formula and worked examples are on our water softener picks.
Hach Total Hardness Test Kit, Model 5-EP (145400)
Drop-count titration · 1 to 30 gpg · each drop = 1 gpg as calcium carbonate · about 100 tests · reagents, measuring tube and mixing bottle in a carrying case · sold by Hach Company on Amazon
If you are about to buy a softener, this is the kit I would use to get the number. Hach’s 5-EP works by counting drops instead of matching a color pad. You fill the measuring tube, add one reagent powder pillow, then add titrant one drop at a time until the sample turns from pink to blue. Hach’s procedure says each drop equals 1 grain per gallon of hardness as calcium carbonate, across a 1 to 30 gpg range.
That gives you a whole-number reading in grains per gallon, the unit our softener sizing guide works in. To get mg/L, Hach says to multiply grains per gallon by 17.1. The procedure also covers well water with iron: high iron or manganese turns the sample orange-brown, and Hach gives an extra step for that case. Hach’s product page lists about 100 tests in the kit. It takes more steps than a strip: Hach says to hold the dropper upright, count every drop and swirl after each one.
- Reads in whole grains per gallon: one drop per grain, per Hach
- 1 to 30 gpg range
- Written procedure for water with high iron or manganese
- About 100 tests in a carrying case, per Hach
- Slower than a dip strip: you count drops and swirl after each one
- Reagents need careful handling; Hach says to review the safety data sheets
- Tops out at 30 gpg
Verdict: The kit to buy when the number decides which softener you buy, or when you are on a well.
Varify Water Hardness Test Kit
Dip-and-read total hardness strips · color chart 0 to 25 gpg and 0 to 425 ppm · read after 30 seconds · strips in a bottle plus sealed pouches · sold by Varify on Amazon
For a fast answer, Varify’s strips are dip and read. Varify’s steps are to dip the strip, take it out right away, let the colors develop for 30 seconds, and match it to the chart. The Amazon listing says the chart runs from 0 to 25 grains per gallon and 0 to 425 ppm, and Varify says the strips work on tap water, wells and appliances.
Varify’s documents do not agree on the strip count. The Amazon listing says 100 strips in a bottle plus two sealed pouches, the product page title on Varify’s site says 150 strips, and the FAQ on that same page says 50. Check the box when it arrives. The sealed pouches are there to keep spare strips fresh, so open one only when the bottle runs out.
- Dip, wait 30 seconds, read, per Varify
- Chart covers 0 to 25 gpg and 0 to 425 ppm, per the listing
- Spare strips in separately sealed pouches
- Works on tap, well and appliance water, per Varify
- Varify’s pages and listing give three different strip counts
- You read a color, not a drop count
- Varify’s pages do not state a shelf life for an opened bottle
Verdict: Buy it to check your water in half a minute, or to spot-check a softener every few months.
JNW Direct Water Hardness Test Strips (150-Strip Kit)
Dip-and-compare total hardness strips · 150 strips · color chart · includes an eBook on water hardness · sold by JNW Direct on Amazon
JNW Direct sells this as a 150-strip pack and says it is an easy way to see if your water softener is working. That is the right use for it: test a softened tap and an unsoftened one, and compare the two readings. The listing says you dip the strip and compare it with the color chart.
The listing also says the strips work on well water, dishwashers, showers and reverse osmosis systems, and that the kit comes with an eBook for recording results. JNW Direct’s own page gives only the strip count and the softener-check use; it does not publish a range, so read the scale off the color chart in the kit. This is the same strip kit we list as a part on our water softener picks.
- 150 strips, per JNW Direct
- Made for checking whether a softener is working, per JNW Direct
- Dip and compare with the color chart
- Includes an eBook for tracking results
- No published range on the maker’s page
- Reads a color, not a drop count
- Maker’s page is a single short listing
Verdict: The strip pack for long-term softener checks, with plenty of strips to test often.
I send an occasional note when a new guide goes up — repairs worth doing yourself, and the parts that actually last. No spam, no course funnel; written by a licensed Georgia plumber.
For Well Owners: Varify 17-in-1 Water Test Kit
If you want hardness plus a wider look at well water, the Varify 17-in-1 Complete Water Test Kit tests 17 parameters, including pH and total hardness, per Varify. Varify says it comes with 100 strips sealed in 5 packs of 20, plus 2 coliform bacteria tests that take 48 hours. Treat it as a home screen. The US EPA says to test a private well every year for total coliform bacteria, nitrates, total dissolved solids and pH, and to use only laboratories certified for drinking water testing; your local health department may test a private well for free, per the EPA.
Before You Buy
- Buying a softener soon? Get the drop-count kit for a whole-number gpg reading.
- Checking a softener you own? Strips are faster, and a big pack lets you test often.
- On a well? Plan for iron as well as hardness, and get a certified lab test for safety.
- Know your units. Divide ppm or mg/L by 17.1 for grains per gallon.
- Keep strips sealed. Close the bottle right away and keep spare pouches closed.
FAQ
How do I test my water hardness at home?
Use a drop-count kit or a dip strip. With the Hach 5-EP you add a reagent pillow to a measured sample, then count drops of titrant until the color turns from pink to blue; each drop is 1 gpg. With Varify strips you dip the strip, wait 30 seconds and match it to the chart.
How do I convert ppm to grains per gallon?
Divide by 17.1. Hach’s mg/L procedure says to divide the mg/L result by 17.1 to get grains per gallon, and its gpg procedure says to multiply by 17.1 to go the other way.
Are test strips accurate enough to size a water softener?
Plumber’s note: for most homes, yes. None of the strip makers’ pages we read gives an accuracy figure, so treat a strip reading as an estimate. A strip reads as a color band on a chart, while a drop-count kit like the Hach 5-EP gives a whole-number reading, one drop per grain. Use the drop kit when your strip reading falls between two softener sizes or you are on a well with iron.
How do I check if my water softener is working?
Test a softened tap, such as a bathroom sink, and an unsoftened one, such as an outdoor spigot if it is plumbed before the softener, and compare. JNW Direct sells its strips as an easy way to see if a softener is working. If the softened tap reads close to the raw water, see our guide to a softener that is not regenerating.
Should I test my well water for more than hardness?
Yes. The US EPA says to test a private well every year for total coliform bacteria, nitrates, total dissolved solids and pH, and to use a certified drinking water lab. A strip kit is a quick screen at home, not a replacement for a certified lab test.
Why Trust Plumbing Picks
Plumbing Picks is written by a licensed Georgia journeyman plumber. Every spec here comes from the maker documents linked below, or from the Amazon listings we link; nothing comes from hands-on testing. On October 4, 2026, every linked listing was in stock and sold by the maker’s own Amazon store. If you buy through a link we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.
Sources
- Hach: Hardness Test, 1–30 gpg, test kit 145400 (Model 5-EP) procedure DOC326.98.00020, Model 5-EP product page, 5-EP mg/L version procedure DOC326.97.00111
- Varify: Water Hardness Test Kit product page
- JNW Direct: water test strips (Water Total Hardness Test Kit)
- Varify: 17-in-1 complete water test kit product page
- US EPA: Protect Your Home’s Water (private well testing)
- Amazon listings for the Hach 5-EP, Varify hardness kit, JNW Direct 150-strip kit and Varify 17-in-1 kit (linked above)
Bottom Line
Use the Hach 5-EP when the number decides which softener you buy, especially on a well. Use Varify or JNW Direct strips for quick checks once a softener is in. Test raw water for sizing, test a softened tap to check the softener, and divide ppm by 17.1 to get grains per gallon.