If your Lake St. Louis home has a water softener, you may have noticed that the plants near the house look different than they did before. Softened water works well for showers and laundry, but it is not the same as plain water for the soil. This guide covers what changes, what stays the same, and how to decide what to water with.
What a softener does to the water
A standard softener removes hardness minerals, mainly calcium and magnesium, by swapping them for sodium on a resin bed. The water that comes out feels softer and slicker, but it carries more dissolved sodium than the water that went in. Some homeowners use potassium chloride in place of salt, which changes the added ion but still adds dissolved material. Either way, softened water is different from untreated water, and plants respond to what is in the water they receive.
Why Lake St. Louis water makes this worth checking
Public water reports for Lake St. Louis describe the tap water as very hard, with a pH on the high side. That means many homes run a softener, and many homes end up watering plants with softened water by default. The area draws on a mix of river water and groundwater, so the starting point can vary from one neighborhood to the next. If your house is on a private well, the starting point may be quite different again, with possible iron, a rotten-egg odor from hydrogen sulfide, nitrates, or other constituents depending on the well.
Where softened water tends to cause trouble
- Potted houseplants watered from a softened tap, especially containers with little drainage.
- Garden beds close to the house, where softener discharge or irrigation runoff returns to the soil.
- Lawns watered with softened water through a long growing season.
- Salt-sensitive plants, including many ornamental perennials, some shrubs, and certain container herbs.
Check the outdoor spigot first
Many softened homes have the softener on the whole-house supply, which means the outdoor hose bib gets softened water unless the plumbing includes a bypass. Trace the pipe that feeds your garden faucet. If it runs after the softener, your lawn and beds are getting softened water. A plumber familiar with your home can tell you whether a bypass exists, and you can ask the question at your next service visit.
Test before you change anything
Guessing is not enough. A basic water test can show hardness, sodium, and pH, and for private wells it can also cover iron, nitrate, and bacteria. Lake St. Louis homes on a private well have an extra reason to test. The wider service area includes the former Weldon Spring cleanup site, and deep eastern Missouri bedrock aquifers can carry naturally occurring radium. Current municipal radium readings are within limits, but that does not tell you what is in a private well. If you are on a well, ask the lab to include radionuclides in the test panel.
Practical options for watering
- Collect rainwater in a barrel or other container for garden beds and pots where practical.
- Run the outdoor spigot on an untreated line if your plumbing allows it.
- Water houseplants from a tap that bypasses the softener, or fill a jug from an unsoftened source.
- Water deeply and less often so that salts do not collect in the root zone.
- Flush containers and beds with plain water a few times each season so that accumulated salt has somewhere to go.
Watch for signs in the soil and leaves
Look for crusty residue on the soil surface or pot rim, leaf edges that brown from the tips, lawn patches that thin out near the house, and poor growth in containers that get watered often. These signs have many possible causes, so test the soil and the water before deciding. A soil test through a local extension office can show salt levels and nutrient balance.
Making the decision
For most Lake St. Louis homes, the practical answer is simple. Keep softened water for the house, and give plants water from an unsoftened source wherever you can. Test first so you know what is in your water, check the outdoor line, and adjust your watering habits. If the answer involves plumbing changes, have the work scoped by someone who will explain the options in writing before you commit to anything.