If you live in San Dimas long enough, you start to notice your water. The white spots on glasses. The crust on the showerhead. The way coffee tastes slightly different after a heavy rain. That is usually when people install a water filtration system, or a softener, or a reverse osmosis unit under the sink.

Sooner or later, though, every system has a bad day. A leak under the cabinet at 10 p.m., no water coming from the RO faucet, or water that still feels hard after you spent good money on a filter. The question becomes practical very quickly: can you safely repair your water filtration system yourself, or is this a job for a local plumber who works on San Dimas homes every week?

A good answer starts with understanding how these systems work, where they usually fail, and how that fits with the kind of water we get in San Dimas.

A quick look at San Dimas water

Before talking tools and repairs, it helps to know what you are filtering.

San Dimas is in the San Gabriel Valley, in a region known for relatively hard water. Much of the local supply comes from groundwater and imported sources managed by agencies like Three Valleys Municipal Water District and delivered by providers such as Golden State Water Company and neighboring city systems. The exact provider depends on your address, but the pattern is similar:

The tap water generally meets state and federal safety standards. It is considered safe to drink from a regulatory standpoint, but it often has:

Noticeable hardness from calcium and magnesium
Chlorine or chloramine for disinfection
Occasional taste and odor changes after system maintenance or seasonal shifts

So if you are wondering, “Is San Dimas water safe to drink?”, the regulated answer is usually yes. But “safe” is not the same as pleasant. That is why many homes add point of use systems at the sink, whole house water filters, softeners, or reverse osmosis for drinking water.

The kind of water we have matters because it drives what gets installed, which in turn shapes what goes wrong.

What is a water filtration system, really?

People use “water filtration system” to mean a few different things. In practice, most San Dimas homes with filters fall into one or more of these categories:

Under sink filters

Compact cartridges or small multi stage systems that sit under the kitchen sink. They usually improve taste, remove chlorine, and reduce some contaminants. Some are simple carbon filters, others are more advanced.

Reverse osmosis (RO) systems

These use sediment and carbon prefilters, a semi permeable membrane, and a small storage tank to produce low mineral water. They are common for drinking and cooking. RO is also the system most likely to prompt the question “Why is my reverse osmosis system not producing water?”

Whole house water filters

These larger tanks or cartridge housings treat all water entering the house. They can target sediment, chlorine, taste and odor, or specific contaminants depending on what is installed.

Water softeners

While not technically a “filter” in the same sense, softeners are often lumped together. They exchange hardness minerals for sodium or potassium to prevent scaling. Many households combine a softener with a separate filter.

Each system has moving parts, seals, and cartridges that age. Understanding how a water filtration system works at the basic level gives you a huge advantage when something goes wrong.

How does a water filtration system work?

The details vary, but most residential systems rely on a few key steps:

Physical filtration

Sediment filters, usually rated in microns, strain out sand, rust, and other particles. If you see cloudy water that clears from the bottom up in a glass, it is often trapped air or fine particulate. If your filter keeps clogging, the sediment stage is doing its job but may be undersized or overdue for replacement.

Chemical adsorption

Activated carbon is the workhorse here. It grabs chlorine compounds and many organic chemicals, which is why it dramatically improves taste and odor. If your filter is not removing chlorine, that carbon is likely spent or the flow rate is too high.

Ion exchange

Common in softeners and some specialized filters, ion exchange swaps one ion for another. In a softener, calcium and magnesium are replaced with sodium or potassium. If your water is still hard after filtration, the resin may be exhausted, the softener may not be regenerating correctly, or the system may be bypassed.

Membrane separation

Reverse osmosis systems push water through a semi permeable membrane. Dissolved solids are rejected and sent to drain while purified water is stored in a tank. If your RO system is slow or not producing water, the membrane, prefilters, storage tank, or feed valve may be at fault.

Once you see your system as a chain of stages, troubleshooting becomes more logical. You are not just staring at a jumble of tubes and plastic housings; you are asking what part of the chain has failed.

Typical lifespans: filters, membranes, and systems

“How do I know if my water filter is bad?” often comes down to age and use.

General ranges, assuming San Dimas style water and normal household demand:

Sediment and carbon cartridges: often 6 to 12 months, sometimes sooner with heavy use or high sediment
Reverse osmosis prefilters: usually 6 to 12 months
Reverse osmosis membranes: commonly 2 to 5 years
Whole house carbon tanks: from about 5 to 10 years depending on design and water quality
Water softener resin: often 10 to 15 years, though iron or poor maintenance can shorten that

“How often should water filters be replaced?” depends on the manufacturer’s schedule and what your water is doing to them. Poor taste, chlorine breakthrough, slow flow, or visible discoloration of cartridges are all signs you may be beyond the recommended interval.

As for the system itself, “How long do water filtration systems last?” is a broader question. Most well built units can run 10 to 20 years with proper maintenance. Cheap plastic housings and no name components fail much sooner. At some point you reach the point where it is cheaper to replace the system than to keep nursing it along.

The most common water filter problems you will see

After years of crawling under sinks and around water heaters, a pattern emerges. The same complaints surface again and again:

“Why is my water filtration system not working?”

The catch all phrase. Often this means no water, very little water, or water that tastes no better than tap. In practice, it usually comes down to clogged filters, closed valves, a failed pressure tank, a bypass that is accidentally left open, or an electrical issue on powered units.

“Why is my water filter leaking?”

Leaks often start with loose housings after cartridge changes, worn O rings, cracked filter sumps, or tubing connections that were not pushed fully into quick connect fittings. Occasionally, freezing or physical stress on the piping will crack plastic parts.

“Why is no water coming out of my water filter?”

For simple under sink units, this is commonly a clogged cartridge or a shutoff valve that was never reopened. For RO units, it might be a bad tank, a clogged flow restrictor, or an automatic shutoff valve that has failed.

“Why is my reverse osmosis system not producing water?”

Here, you start methodically: is there feed water to the system, is there pressure, are prefilters clogged, is the membrane old, is the storage tank waterlogged, or is a valve closed? RO systems like to stop working quietly when neglected.

“Why is my water filter making a noise?”

Hissing or whistling usually points to air in the line, high flow through a small or partially blocked passage, or vibration against cabinetry. On RO units you might hear gurgling as reject water flows to the drain.

“Why is my water filtration system slow?”

Low pressure after a filter change often means trapped air, a clogged cartridge, undersized plumbing, or a storage tank that has lost pressure. It can also follow a municipal water pressure drop in your area.

“Why is my filtered water cloudy?”

Fine air bubbles, which often clear from the bottom as the glass sits, are usually harmless and often show up after maintenance. Milky water that does not clear, or that leaves particles at the bottom, can point to disturbed sediment or failing cartridges.

“Why does my filtered water taste bad?”

Old carbon, bacterial growth in stagnant parts of the system, high total dissolved solids if the membrane has failed, or simply a change in the source water can all affect taste. If it comes on suddenly, that is a reason to pay attention.

“Why is my water still hard after filtration?”

Many filters do not soften at all. If you have a softener and still feel hardness, there might be bypass plumbing, a stuck valve, exhausted resin, or incorrect settings. A water softener not working with your filter properly can also happen if they are plumbed in the wrong order.

A trained plumber recognizes these patterns in a couple of minutes. With some basic knowledge, you can too.

DIY vs pro: which problems can you safely handle?

Here is a useful way to think about it. You ask two questions:

Is this likely a consumable or an adjustment, or is it a structural or high pressure issue?
If I guess wrong, what is the worst that realistically happens?

Typical DIY safe tasks include:

Replacing standard under sink filter cartridges when you can easily access the housings
Changing RO prefilters and postfilters following the manufacturer’s instructions
Resetting a filtration system controller according to the manual
Repressurizing a reverse osmosis storage tank if you are comfortable with a tire gauge and valve
Cleaning and lubricating O rings with food grade silicone

On the other hand, a San Dimas plumber or filtration specialist should almost always handle:

Persistent leaks you cannot locate, especially in walls, ceilings, or slabs
Re piping, moving, or newly installing whole house systems
Diagnosing water pressure drops that affect the whole house after a filter install
Electrical issues with UV systems, booster pumps, or control heads
Systems that have frozen, cracked, or visibly burst

If you are the kind of homeowner who can swap a faucet or install a garbage disposal, many under sink filtration tasks are within reach. If the idea of turning off a main shutoff valve makes you nervous, err on the side of calling someone who works with water under pressure every day.

How to diagnose a problem without guesswork

You do not need to be a professional, but you do need a method. When a client asks, “Can I repair my Water Filtration Repair San Dimas water filtration system myself?”, I walk them through a simple mental checklist over the phone before I ever roll a truck.

First, identify the type of system

Under sink cartridge, RO, whole house filter, softener, or a combination? Look for the brand and model number printed on labels, tanks, or control heads.

Second, clarify the symptom

Is it a leak, low flow, no flow, bad taste, hardness, or noise? Narrowing it down keeps you from changing parts that are not related.

Third, check the obvious

For “Why is no water coming out of my water filter?”, verify that the feed valve is open, the main water is on, and no one has recently turned a bypass or shutoff. For taste problems, note when the last cartridge change happened.

Fourth, match the symptom to the likely stage

Bad taste and chlorine breakthrough point at carbon filters. Hard water points at softener function. Very slow flow through an under sink filter after months of use points at a clogged cartridge.

Fifth, decide whether the repair is just parts, or plumbing

If the fix is “change this cartridge” or “reset this control”, you may be on solid DIY ground. If the fix is “cut and re pipe 1 inch copper and install a new bypass”, that is a strong sign to call someone who does this weekly.

This approach also helps you talk intelligently with a plumber. Instead of “my filter is broken”, you can say “my RO tank is full but I only get a trickle from the faucet, and the system is 5 years old”. That level of detail often saves you time and money.

Costs: repair vs replacement

Money is usually the tiebreaker between do it yourself and professional help.

“How much does a water filtration system cost?” varies enormously. Under sink systems can be as little as a hundred dollars for a basic unit to over a thousand for high end RO with remineralization. Whole house filters and softeners often range from several hundred dollars for a basic big box setup to several thousand for quality, professionally installed systems.

“How much does it cost to repair a water filtration system?” is more specific:

Minor DIY friendly costs might include:

Replacement cartridges: typically in the 20 to 150 dollar range depending on the system
New O rings, fittings, or tubing: usually under 30 dollars in parts
A replacement RO tank: often 80 to 200 dollars

Professional repair in San Dimas might run from a modest service call fee and an hour of labor for a simple fix, up to several hundred dollars if multiple components need replacement or access is tricky.

“Is it worth repairing a water filtration system?” comes down to age, build quality, and how close you are to a natural upgrade point. If your under sink unit is 15 years old, parts are brittle, and cartridges are hard to find, replacing the entire system might be the smarter move. On a relatively new, high quality system, repairs usually make sense.

“Is it cheaper to repair or replace a water filtration system?” is not only about today’s invoice. A cheap replacement that uses hard to find proprietary cartridges can become more expensive over five years than a higher quality system that takes standard filters available locally.

When filters misbehave: specific symptoms and what they mean

Several of the most frustrating issues tend to repeat in San Dimas households.

Water filter leaking at the housing

Often, the cause is a pinched or dry O ring, or a housing not fully tightened after changing a water filter cartridge. Turning things “just a little tighter” sometimes cracks the housing, so the fix is not more force but cleaning, inspecting, lubricating, and then snugging the housing evenly.

Stuck water filter housings

If you are wondering how to remove a stuck water filter, the key is controlled force. Use the proper housing wrench, relieve pressure by opening a nearby faucet, and avoid banging on plastic with metal tools. If the housing is distorted or thinks it is now part of the plumbing forever, that is a moment to decide if a plumber should take the risk of breaking it on their time instead of yours.

Low water pressure after a filter install

“What causes low water pressure after a water filter?” is usually one of three things: a clogged or undersized cartridge, a partially closed valve, or restrictive fittings on a whole house system. Sometimes the system was plumbed in series with too many devices. A plumber with a pressure gauge can quickly see where the drop occurs.

Water filter not removing chlorine

If you can still smell or taste chlorine under normal municipal conditions, the carbon is probably exhausted or the flow rate is higher than the system is designed for. Occasionally, a system simply was not sized for the actual usage in the home. That is not a DIY mistake; that is a design oversight.

Filtered water cloudy or with bubbles

If you recently changed filters or serviced the system, trapped air is the first suspect. Let the water run for a few minutes at low flow. If the cloudiness persists and does not act like tiny bubbles, you may have fine particulate getting past filtration or a disturbed line.

RO system producing little or no water

“How do you repair a reverse osmosis system?” starts with measuring output and testing TDS (total dissolved solids) if you have a meter. Very low production can be a sign of a plugged membrane, a failed flow restrictor, low feed pressure, or a storage tank that has lost its air charge. Some of these are DIY tasks; others, particularly involving feed pressure and drain line routing, are better left to a professional.

Hard water despite filters and softener

“Why is my water softener not working with my filter?” is often a question of order and settings. Usually, the softener should be first in line, with carbon or other filtration after it unless a specific contaminant issue changes that plan. If a system was installed without considering San Dimas hardness levels, the softener may be too small or regenerating too infrequently.

Maintenance: what your system really needs

Every system, from the cheapest pitcher to the most elaborate whole house RO, needs routine care. The maintenance tasks vary, but the goals are the same: keep flow where it should be, keep taste where you want it, and prevent unnoticed leaks.

At a minimum, ask yourself:

How often should water filters be replaced?

Mark the date on the housing or keep a simple log. If the manufacturer says 6 months, do not stretch it to 2 years just because water still comes out. Chlorine and contaminants break through long before flow completely stops.

How often should a water filtration system be serviced?

A quick check once or twice a year catches small issues. Look for signs of moisture around fittings, corrosion on valves, shredded O rings, and any plastic that is yellowing or cracking.

How do I reset my water filtration system?

Some electronic heads require a specific sequence to reset timers or service indicators. Keep the manual in a folder or download a PDF and store it where you can find it on your phone. Blindly pushing buttons is how people accidentally wipe out well tuned settings.

What maintenance does a water filtration system need?

Beyond filter changes, some systems need regular sanitizing, especially RO units and any system that sits unused for long periods. Softeners need salt level checks, occasional brine tank cleaning, and periodic verification of hardness settings to match actual San Dimas water.

Neglect makes repair questions more urgent and expensive. Modest, predictable maintenance makes most of the scary failures relatively rare.

Matching the system to San Dimas water

Choosing or upgrading a system is itself a form of repair. If your current setup constantly fights the local water chemistry, you are pushing a boulder uphill.

For hardness, many homeowners ask, “What is the best water filtration system for hard water?” The honest answer is that filtration alone usually is not enough. For true scale control across the home, a properly sized softener or a well designed alternative conditioning system is the most reliable approach. Filters handle sediment and chlorine; softeners handle hardness.

If you care mostly about drinking water taste and safety, a good under sink system or RO unit, maintained on schedule, usually does the job. Knowing what is in San Dimas tap water from the latest water quality report helps guide cartridge choice. If your provider uses chloramine instead of free chlorine, for instance, you need cartridges that are rated to handle it.

If you ever doubt the system’s performance, basic tests help. A simple hardness strip can tell you if the softener is working. An inexpensive TDS meter gives clues about RO membrane health. These do not replace professional testing, but they help you decide whether you are looking at a quick DIY filter change or a call to someone who repairs water filtration systems professionally.

So, do you really need a San Dimas plumber?

You can absolutely change many cartridges yourself. You can learn how to change a water filter cartridge safely with a wrench, a towel, and the manual. You can reset simple controllers and increase water pressure on your filtration system when the cause is a clogged prefilter or a soft RO tank.

Where a local plumber or water treatment specialist earns their keep is in the gray areas:

Tracing leaks inside walls that started at a filter connection.

Rebuilding aging whole house systems that are slowly starving your home of pressure. Sorting out complex setups with a softener, whole house carbon, and under sink RO that were installed piecemeal over years by different people.

If you are confident with tools, willing to learn, and dealing with a straightforward under sink system, repairing your water filtration system yourself is reasonable. If you are staring at a maze of valves and tanks in the garage and wondering where the main shutoff is, a San Dimas plumber who works with these systems daily is not a luxury. It is protection for your home, your time, and your peace of mind.

Alpine Plumbing, Heating, and Air
462 Borrego Ct, San Dimas, CA 91773
6266081032

Can I Repair My Water Filtration System Myself or Do I Need a San Dimas Plumber?