How to Make a DIY RV Water Filter System

There are plenty of perks to owning an RV, but clean, tasty water isn’t one of them.

There’s no need to rely on your built-in RV water filter (if you’re lucky enough to have one, it probably won’t trap enough contaminants to make a big difference to your water quality). You can make your own RV water filtration system following the steps in this guide.

👍 Why Make Your Own RV Water Filter System?

There are plenty of reasons why you should consider making your own RV water filter system:

• Flexibility. You get to choose which filters you use, so you can target specific contaminants that you know are problematic in your local campsites. You can also modify the filtration system however you want at any point throughout its lifespan.
• Effectiveness. The built-in water filters in RVs are usually lacking. You might have an inline carbon filter that improves water’s taste, but doesn’t do much else. When you make your own RV water filtration system, you can include a series of water filters that provide a much more effective overall filtration performance. That means better protection for your hot water heater and other water-using appliances in your RV.
• Ease of maintenance. Since you know exactly what your DIY RV water filtration system is made from, you should find it easier to replace the filters and perform other maintenance and troubleshooting tasks.
• Wallet-friendly. Making your own RV water filter rather than buying a pre-fabricated system will help you save hundreds of dollars. Plus, you can cut your water bottle habit, so you’ll save money in that respect, too.
• Simplicity. Building a DIY RV water filtration system is easier than you’d think. You won’t need to buy many materials, and you should already have the tools you need on hand.

👎 Setbacks of Building Your Own RV Water Filtration System

Of course, not every aspect of making your own RV water filtration system is positive. You should also consider the setbacks of DIY RV water filters:

• Time-consuming. It’ll take you a good few hours – and a lot of patience – to make your own RV water filter. Expect a lot of time doing fiddly tasks and multiple trips to your local hardware store.
• Quality control. Buying a pre-fabricated system from a reputable manufacturer essentially guarantees good quality, but the same can’t be said for your own workmanship. Even if everything looks perfect, the risk of leaking and other design issues is higher.
• All on you. You’ll have to be happy to put in the time and effort to do this project yourself. A professional plumber probably won’t agree to install a DIY water filtration system.

📋 How to Make an RV Water Filtration System: Step-by-Step

Follow the steps below to make your own water filtration system for your RV.

Step 1: Test Your Water (optional)

If you’re staying local in your RV for a while, you’ll benefit from testing your local campsite’s water supply and finding out exactly what it contains – and what you want to remove.

You can keep costs low by buying a DIY test kit that detects contaminants you’re likely to find in a campsite water supply, like microorganisms, heavy metals, nitrates, and other problematic impurities. You can buy a decent test kit for less than $20 online.

Or, consider private laboratory testing if you have a bigger budget and want to get a clearer idea of exactly how contaminated your water supply is. Private lab testing is more expensive – usually around $100-$200 for a test kit – but provides more thorough, accurate test results.

📌 You don’t HAVE to test your water if you don’t want to. Testing probably also doesn’t make sense if you regularly travel from one place to the next – you don’t really want to test the water in every camping site you stop at.

If testing sounds like too much hassle, just assume that your water contains the most likely contaminants: sediment, microorganisms, and impurities affecting water’s taste and odor.

Step 2: Gather your Materials

Next, gather all the supplies and tools you’ll need to install your filter.

Your exact items will depend on what you want to build. We’ve shared an example list below.

Commonly-needed supplies:

• Pipe cutter/hacksaw
• Drill and drill bits (various sizes)
• Adjustable wrench
• Plumber’s tape
• Screwdriver
• Tubing
• Bucket
• Shut-off valves
• Connectors, like push fittings and elbow tees

Optional supplies:

• Pressure gauges
• Mounting bracket
• Bypass valves

Step 3: Design Your Filter

Now onto the exciting task: designing your filter. Do some research, draw a diagram, and make a list of the main components that you want to include.

We’ve shared the components you will most likely use below.

Water Filters

We recommend including at least two, preferably three filters in your RV water filtration system. This will allow you to target the three most likely groups of contaminants: sediments, microorganisms, and contaminants affecting water’s taste and odor.

The type and size of filter cartridges you buy depend on the type of filtration system you plan to build. Do you want a whole home filter system that sits in your RV’s dedicated filter and water softener space? Or do you want a filter with a pump that you can use to purify all types of natural water sources, like lakes and rivers? Or do you want an under-sink RV filter that just treats your drinking water?

Buy the filter housing first, then look for filters that fit inside the housings. Make sure the filter housing is the right size and accommodates the right water flow rate for your intended use point.

There are no limits to the types of filter cartridges you choose. Pick your filters based on the contaminants that cause the most issues in your RV water supply. We recommend focusing your search on filters that have NSF certifications for their contaminant removal abilities so you can rely on their performance.

Filter Type

What types of filters should you consider for an RV water filter unit? We’ve shared a few recommendations below.

• Sediment Filters: These filters come first in most water filtration units. They’re designed to target suspended particles of sand, dirt, rust, debris, and other common sediments in RV water supplies. They also protect later filter stages from early clogging due to sediment in the water.
• Activated Carbon Filters: There are a couple of types of activated carbon filter cartridges you can use in an RV system, including granular activated carbon (GAC) and carbon block filters. Carbon filters have a pore size of around 5 microns and remove contaminants affecting water’s taste and smell, like chlorine.
• Iron & Manganese Filters: These filters target iron and manganese, two contaminants commonly found in groundwater RV supplies.
• Nanofilters – To target contaminants like bacteria and viruses, you need a nanofilter. Microorganisms are small enough to fit through the pores of most standard filters, and nanofilters have tiny pores – usually at least 0.2 microns – to trap these impurities. Look for absolute micron filters, which have filter pores of all the same size, enabling them to remove up to 99.9% of most common microbes.

For most people, the best order of filter cartridges in an RV system is:

1. Sediment filter
2. Carbon filter/ iron & manganese filter
3. Nanofilter

This order is best because it starts with the filter with the highest micron rating, trapping the largest contaminants, then gradually decreasing in micron rating with every subsequent filter stage.

Shutoff And Bypass Valves

If you’re building a filter that will be plumbed into your RV’s main water line, you’ll need to consider bypass and shutoff valves.

It’s a good idea to install two shutoff valves – one before and one after your filtration system. This means you can shut off the water flowing into and out of the system, which will be your best emergency response if you notice a leak, and will make maintenance quicker and safer.

You can go one step further by installing a bypass valve, which diverts the water supply around the system to give you access to (unfiltered) water if the filtration system isn’t in use.

Pressure Gauges

Finally, consider installing pressure gauges in your DIY RV system to keep an eye on your water pressure.

A pressure gauge reading will drop to indicate clogging of a filter cartridge, so it’s clearer when you need to buy new filters.

You can install a single pressure gauge before the entire system, or one gauge before each filter stage.

Water Pressure Regulator

It’s common to experience varying water pressure in a campground.

If you want adequate water pressure to run your appliances, it’s worth installing a water pressure regulator as part of your RV filtration system. That way, you’ll get consistent water flow as you filter water for your RV.

Step 4: Install the System

Once you’ve gathered your materials and filters, you can now assemble the system and install it in your chosen installation location.

Simply slot the filter cartridges into the filter housings and attach the housing to your water line.

You can use videos and guides on how to install an RV filtration system to learn how to safely connect your DIY system to your water line.

Step 5: Try Your Filtered Water

The installation is now complete, and there’s nothing left to do aside from trying it out.

Switch on your water supply, open a drinking water faucet, and check for leaks around the filter connections. If you notice leaks, switch off your water supply and apply more plumber’s tape or further hand-tighten the connections.

Fill a glass with drinking water and taste it. If it’s safe to do so, you can compare the water with the untreated campsite water.

To get the best understanding of your DIY RV filter’s capabilities, test your water before and after filtration and compare the results.

📝 Installation Tips

There are a few things to keep in mind when building DIY RV water filtration systems:

• Make sure you install the system in the best location. Generally, this should be as close as possible to your RV water supply’s entry into the RV. You could also install an inline RV water system along the water pipe leading to your RV.
• If it makes more sense to install the filter system outside, you’ll need to protect it from the elements. Use a waterproof, UV-resistant, frostproof water filter cover, or build a cupboard around the unit to offer the same protection.
• Avoid using a metal wrench to tighten plastic fittings. It’s always best to hand-tighten and use plumber’s tape to make a seal when necessary.
• Once you’ve installed the system, your work isn’t over for good. You’ll need to maintain the system by replacing the filters (usually every 4-6 months) to keep it in good working order.

Sound like too much of a project after all? Check out our favorite pre-fab RV water filters of 2024

❔ FAQ

Which water filters should you use in an RV filter system?

We recommend using sediment filter cartridges, carbon filters, and nanofilters in an RV filter canister system. These three filter types combined will remove large, medium, and small contaminants from your RV water, improving water’s taste and protecting your appliances.

Can a DIY RV filter prevent mineral buildup?

No, you can’t prevent mineral buildup in your water heater and other appliances with a homemade RV filter system. While certain filter types can prevent iron deposits, no RV filter can produce soft water. You’ll need a dedicated RV water softener for that.

How much does a DIY RV water system cost?

The cost of making your own RV filtered canister system is around $250-$450. The cost depends on the types of filters and other supplies you buy.

What are the most common contaminants in RV water?

RV water from a campsite is usually sourced from a private well, so it contains common well water contaminants like heavy metals (arsenic, mercury, cadmium), fluoride, manganese, iron, nitrate, and volatile organic compounds. It’s also at a greater risk of bacterial contamination than municipal drinking water.