You probably do not need whole-house reverse osmosis just because you live in Cabo.
But every Cabo property should understand four separate questions:
- Are particles entering the system?
- Is the cistern or tinaco being managed as part of the water system?
- How hard is the water — measured as hardness, not guessed from TDS?
- How will drinking water be treated?
Those are four different problems. They should not be solved with one oversized filter package.
The MirAqua principle: diagnose first
Cabo water can vary by source, delivery method, storage condition and treatment already installed at the property. A system that is appropriate for one home can be unnecessary or incomplete for the next.
Start with observation and measurement:
- inspect the cistern/tinaco and lid;
- understand the source where practical;
- look for incoming sediment;
- measure TDS/EC as a mineralization screening tool;
- measure hardness directly in mg/L as CaCO3 or grains per gallon (gpg);
- measure free chlorine when disinfectant residual matters;
- use laboratory testing when microbiological or specific chemical safety needs to be established.
A TDS meter is useful, but it is not a hardness test and not a safety test.
Level 1 — Keep particles out
For many Cabo properties, sediment protection is the first practical upgrade.
Depending on how the property fills, that may mean:
- a washable inlet screen or bag filter;
- a spin-down prefilter;
- a properly sized cartridge sediment filter;
- staged coarse-to-fine filtration where particulate loading is high.
Sediment filtration can protect pumps, valves and downstream treatment from suspended solids. It does not remove dissolved hardness and it does not make microbiologically unsafe water safe by itself.
The correct micron rating and housing size depend on flow, fill method and the amount of material actually entering the property.
Level 2 — Manage the cistern or tinaco
Your storage tank is part of the water system whether you actively manage it or not.
Check:
- lid and vent integrity;
- sediment accumulation;
- visible deposits or biofilm;
- cleaning history;
- water turnover;
- free-chlorine residual where chlorination is being relied upon.
Free chlorine does not last for a fixed number of days in every tank. In stored household water it can fall below a useful residual in hours to several days, depending on starting residual, temperature, chlorine demand, sediment, organic matter, tank condition and other chemistry.
A clean, covered tank with low chlorine demand may retain residual for several days or longer. A dirty or high-demand tank can consume residual much faster. The reliable answer is to measure the property, not use a universal calendar rule.
Cleaning, inspection and a properly designed disinfection strategy can be appropriate. Chlorine, UV, ozone and electrolysis are not interchangeable technologies and should not be selected without considering the complete system.
Level 3 — Measure hardness before deciding how to control scale
Los Cabos has documented groundwater sources that are hard, and some historic samples have been very hard. But the level varies materially by source and over time.
Hardness should therefore be measured directly.
Hardness: calcium and magnesium, normally expressed as mg/L as CaCO3 or gpg.
TDS: the total dissolved ionic/mineral content. It does not tell you how much of that total is hardness.
If measured hardness is high and the goal is to actually reduce calcium and magnesium, a correctly sized ion-exchange water softener is the standard technology to evaluate.
Polyphosphate, Siliphos and many salt-free devices should be described as scale-control or conditioning technologies, not as true softeners unless they actually remove hardness ions.
RO can also reduce hardness in the water it treats, but whole-house RO is usually a much more complex solution than is necessary when hardness is the principal problem.
Level 4 — Decide how you want to treat drinking water
Drinking-water treatment should be a separate decision from whole-house sediment or scale treatment.
Possible approaches include:
- certified carbon treatment where taste, odor or chlorine are the target;
- point-of-use reverse osmosis where substantial dissolved-ion reduction is desired;
- validated UV as part of a microbiological barrier when the system’s dose, flow, water clarity and maintenance support that objective;
- other contaminant-specific treatment when testing identifies a particular issue.
Do not assume that a whole-house sediment/carbon filter produces water equivalent to a properly designed drinking-water system.
Three practical system levels
Minimum
Inspect + measure + sediment protection + defined drinking-water strategy.
For a cost-conscious property with no documented special contaminant issue, this is often the best place to start.
Better protection
Add:
- scheduled cistern/tinaco inspection and cleaning;
- direct hardness testing and scale treatment where justified;
- appropriate carbon or other media for an identified aesthetic issue;
- recurring maintenance for cartridges, salt and treatment equipment.
Full treatment
For properties with measured chemistry, operational requirements or very high expectations, a more integrated system can include:
- staged sediment treatment;
- softening;
- appropriately designed carbon/media treatment;
- validated disinfection;
- point-of-use RO;
- advanced whole-house treatment only when the feed water and use case justify it;
- monitoring and planned service.
When whole-house RO actually makes sense
Whole-house RO can be appropriate for difficult source water or a customer specifically requiring broad dissolved-solids reduction throughout the property.
But it should be engineered around:
- feed-water chemistry;
- pretreatment;
- membrane recovery and reject-water management;
- storage capacity;
- booster pressure;
- remineralization/corrosivity where appropriate;
- membrane cleaning/replacement;
- energy and ongoing operating cost.
It is not the default answer to sediment, dirty storage or hardness alone.
What MirAqua should recommend
We don’t start by asking, “Which filter do you want?”
We start with:
What is the problem? Where in the system is it occurring? What evidence do we have?
Then we build the minimum treatment that solves it — and make sure it can actually be maintained.
Understand your water quality →