There is no single price for "a water filtration system," and anyone who gives you one without asking questions is guessing. A countertop pitcher, an under-sink filter and a whole-house system with a softener are three different products and three different installs. The number depends on which one you need and how hard your house makes it to install.
We do not print dollar amounts in a blog post, because a number out of context misleads more than it helps. What we can do is show you the factors, so a quote makes sense when you get one and so you can spot the line items that deserve a question.
Start with the problem, not the product
The cheapest system is the one that fixes the thing that bothers you. If the complaint is taste and smell, a carbon stage may be all you need. If it is scale on fixtures, filtration is not the right tool and a softener or conditioner is. If it is grit or rust flakes, sediment filtration at the main is the obvious answer.
Starting with a product and working backward is how people end up paying for a five stage system when their issue is one stubborn faucet screen. Describe what you see, smell and taste first.
Six things that set the cost
System type
A single cartridge housing, a multi-housing whole-house setup, an under-sink reverse osmosis unit and a softener each carry a different equipment cost before any labor.
Size and flow capacity
A bigger home with more bathrooms needs a larger housing and cartridge surface so pressure stays good. Bigger parts cost more.
Installation difficulty
Access to the main, pipe material, wall space, how far the filter sits from the shutoff and whether the drain is close all change labor.
Permits and code items
Plumbing work may need a permit, and the Millbrae Building Division handles those. Backflow or drain requirements can add parts.
Upkeep
Cartridge changes, membrane replacement and routine checks are an ongoing cost, which is often larger over a decade than the first install.
Condition of existing plumbing
Corroded shutoffs, worn pressure regulators or a failing line near the main can mean extra work before the filter goes in.
What the Millbrae water report tells you before you spend anything
Read the 2025 report first
The City of Millbrae Public Works Department publishes an annual Consumer Confidence Report. The 2025 edition lists hardness from 8.1 to 112 parts per million, with an average of 62, and chloramine as the disinfectant. The supply is 100 percent SFPUC water. A rough conversion of 62 ppm is about 3.6 grains per gallon, which is our own arithmetic and not a figure printed in the report.
That matters for cost because water at that level is rarely severe enough to make a softener the automatic answer. The water is already treated and disinfected at the source, so the sensible spending usually goes toward the taste, any sediment in your own pipes and protecting appliances. If someone quotes a heavy-duty softener without asking about your scale problems, ask why.
None of this means you should never soften. Some Millbrae households see spotting and scale on fixtures, especially where the range reaches the upper end. The point is that you decide with the report in hand, and not because the first quote offered it.
Where the money tends to go
For a whole-house cartridge system, the biggest share often lands in labor and fittings, not in the housings. Cutting into the main, adding valves and a bypass, setting a bracket and testing under pressure takes skilled time. A system that looks inexpensive online can turn expensive if it needs a wall rebuilt around it.
For reverse osmosis at the sink, labor tends to be shorter, but there are specific extras: a drilled countertop hole, a drain saddle and a place for the tank. For a softener, the drain line, a nearby outlet, a salt supply and bypass plumbing are what add up.
| System | Equipment weight | Install effort | Ongoing cost |
|---|---|---|---|
| Under-sink carbon filter | Low | Low | Cartridge changes |
| Under-sink reverse osmosis | Moderate | Moderate | Cartridges and membrane |
| Whole-house cartridge system | Moderate to high | Moderate to high | Sediment and carbon changes |
| Water softener | High | Moderate to high | Salt and service |
Questions to ask before you accept a quote
A good quote names the system, the stages, the cartridge types, the port size, the install scope and what is included for permit work and cleanup. It also names the replacement cartridges and how often they are needed, so the cost of upkeep is not a surprise. If any of that is missing, ask.
- What problem is this system meant to solve in my home?
- Which cartridge types and sizes are included, and how often are they changed?
- What pipe size and flow rate was the system sized for?
- Does the price cover valves, a bypass, brackets and fittings?
- Who pulls the permit, if one is needed?
- What happens to the drain, the countertop or the wall during install?
- What does the ongoing replacement cost look like?
Hiring and licensing
A contractor who does permit work needs the right license, and the California minor-work exemption does not apply to work that needs a permit. The Contractors State License Board lets you look up a license, and C-36 is the plumbing classification. A price that is lower because there is no permit and no license is a risk that lands on you.
What changes a filtration quote
These are the questions that move the price up or down for a Millbrae home.
System type
A sink filter, a reverse osmosis unit and a whole-house setup are different scopes.
Flow and size
Larger homes need larger housings and more cartridge surface.
Access and layout
Tight spaces, long runs and finished walls add labor.
Permits and code items
Permit work, valves and drains can change parts and time.
Ongoing upkeep
Replacement cartridges and membranes are part of the real cost.
Call the 24/7 line for a clear price before work starts. Any filter quote should list cartridges and change intervals so you can compare the cost of ownership.
Ways to spend less without cutting corners
Treat the point of use before the whole house when only one tap matters. Choose a cartridge size that matches demand, not the biggest option. Ask about combining the install with other plumbing work, because one visit is cheaper than two. If you are already planning a remodel or a new water heater line, the filter connections can be roughed in at the same time.
Buy cartridges on a schedule instead of waiting for pressure to collapse, since a loaded filter can strain a pump or a water heater. Keep a spare set on hand. A cartridge on the shelf is cheaper than an emergency visit.
Next steps
If you want a number tied to your own house, our water softener and filtration service starts with a conversation about your water and a look at your main. For jobs that tie into a remodel, plumbing installation covers the supply, drain and fixture connections in one project.
We cover Millbrae and the neighboring town described on the Burlingame plumber page. The service area page has the rest of our coverage, and the 24/7 line is open whenever you have a question.
Want a real number?
Call the 24/7 line, tell us about your home and what you want fixed in the water. We give a clear price before work starts.
Because system types, sizes and installation difficulty vary. A quote for an under-sink unit and a quote for a whole-house system are not comparable. Ask what is included, especially cartridges, valves and permit work.
Not always. A smaller system that matches your actual problem can serve you better than an oversized one. Watch for cartridges that are expensive or hard to find, since upkeep can outweigh the saving.
Permits may apply, and the Millbrae Building Division handles plumbing permits. If the work cuts into the main or alters piping, ask the contractor who will pull the permit before agreeing on a price.
It depends on the system, but cartridges, membranes and salt are recurring. Over many years, upkeep often rivals the install itself, so ask for the change schedule and cartridge list before you buy.
Not directly. A filter protects fixtures and appliances from particles and can help with taste, but it does not reduce usage. A reverse osmosis unit can add a small amount of drain water.
The annual report from Millbrae Public Works lists hardness, disinfectant and other readings for the 2025 data year. Bring the hardness range and the disinfectant details to any quote conversation so recommendations match your water.
Sources and standards: The City of Millbrae 2025 Water Quality Report. The Millbrae Building Division for permits. The CSLB license lookup. Prices are not quoted.