A shower head that sprays in thin, wandering streams, or one that has slowed to a dribble, looks like a hard water problem. Sometimes it is. But mineral scale is only one of several things that narrow a spray, and each cause has a different fix. Run the checks below before you decide that a softener is the answer.
Start with the pattern, not the feeling
Mineral buildup usually shows up as spray holes that are partly blocked. The stream splits, fans out unevenly, or has dead spots while the rest of the face works normally. Low supply pressure tends to weaken the whole spray evenly, with less force from every hole. Run the water and look closely at the face of the head. If some holes are dead and others are fine, suspect the head. If the whole face is weak, suspect the supply.
Compare the fixtures
Turn on the kitchen faucet, then the bathroom sink, then an outdoor hose bib if you have one. Note whether each one runs strong or weak. A single weak fixture points to that fixture: its aerator, its supply line, or its own shutoff valve. Weak water at every tap points to the supply, the main shutoff, a partly closed valve, or pressure coming in from outside the house. Also check whether the weakness is on the hot side, the cold side, or both. A weak hot side alone can point to the water heater or its inlet line.
Check the aerators and the head
Kitchen and bathroom faucet aerators are small screens that collect the same grit and scale as shower heads. Unscrew the aerator by hand or with a cloth-wrapped tool, rinse it, and look for crust on the screen. Then remove the shower head, which usually needs only a hand twist or a wrench wrapped in cloth, and look at the nozzle face. White or gray crust in the holes, with the holes visibly narrowed, supports a mineral cause. To clean, soak the head in a mild vinegar solution and clear the holes with a soft wire such as a paper clip, taking care not to scratch the face. Reinstall, run the water, and compare the spray to how it looked before.
What a cleaned head tells you
If the spray returns to normal after cleaning the head and aerators, the cause was local buildup. That does not settle whether your water is hard. Cleaning fixes the symptom at one point, and scale will come back if the water is driving it. Keep a simple note of when you clean the head. If the buildup returns on a regular cycle, water chemistry is the likely driver, and a water test is the next step. Get the test before you compare any quotes, so the numbers you are comparing are based on your water. For a shortlist of companies serving the St. Louis area, see Best Water Softener Companies in St. Louis, and for how those rankings are built, read How We Rate Water Softener Companies.
When it is not the water
If the head is clean, the aerators are clear, and every fixture in the house is weak, stop looking at the fixtures. A partly closed valve, a failing pressure regulator, or a supply problem outside the house can cause that pattern. Those are jobs for a plumber or your water utility, not a softener. A softener will not restore pressure that is lost upstream of the house, so do not buy one to fix a spray that was never caused by mineral buildup.